the biggest difference between 4 and 6 axles is tractive effort. 4 axle locomotives hit their high water mark with the GP60 or the B40-8. They were popular on hot trains, like Intermodal where the high horsepower could perform better with 4 axles. Hot trains always had 4 axle units and several of them so they could run at speed and accelerate quickly, also would still make good time if they lost a unit on the run. With the closing of the GP era, Horsepower had already reached 900hp per axle and was not able to hold the rail at lower speeds using that much power, you just couldnt stick that much power to the rail with 4 axles. For the same reason you wouldnt want a lashup of GP60s on a coal drag, they would run fast if they ever made it up to speed but all that horsepower would be useless trying to start or pull a grade, the ammeter would be stuck in the red until you melted the traction motors 😂. If you spread the same power over 6 axles then you have much more thermal capacity and can hold a higher throttle position, putting that power to the rail.
@@djstrains thanks brother, just love sharing all things trains and your channel is one of the best sources for the entirety of the railroad topic. You cover it all DJ, Cheers Rob hope maybe someday to hear one of those air starters. The big old C series Alcos had them, the sound neat 😁😁
The OP isn't entirely accurate. The key point is that power equals force times speed. A four-axle unit can't exert a lot of force on the rail. Not particularly because of the limits of traction motors but because of the limits of adhesion. If you compare a GP60 and an SD60, both have 3800hp, and the SD60 is about 50% heavier and has 50% more axles. Both have the same weight on each axle, which means that both have the same friction (grip) per axle. But, overall, there's 50% more friction between an SD60 and the rails than a GP60. And, by Newton's third law, that means the SD60 can exert 50% more force on the train. It's this increased ability to apply force to the rails (aka, tractive effort) that allows an SD60 to get a heavy train moving, or to haul it uphill. GP60s can do the same thing, except that you need 50% more of them. If your train needs two SD60s to get it moving, it would need three GP60s, even though the GP60s would have 11400hp vs the 7600hp of the two SD60s. If you try to put all 3800hp through the four axles of a GP60 at low speed, the force will exceed the friction between the wheels and the rails, and the wheels will spin. (Power equals force times speed, so high power and low speed means high force.) Indeed, for this reason, many four-axle locomotives have a control system that limits the power at low speed to about the same power per axle as a six-axle unit. This is why slugs are a thing -- instead of being unable to use the extra power at low speed, you put it into another locomotive's traction motors. At speed, putting all that power through four axles is fine, because the force generated is relatively low -- but still enough to keep the train moving. A six-axle unit could do just as well at those speeds, but there's no point hauling all that extra weight around. At least, that used to be the philosophy. Now they figure they may as well just use six-axle units for everything and save the inconvenience of having multiple types of locomotive. And you can't use a slug at high speed, because the mother-slug pair doesn't have enough power to generate enough force at high speed to keep the train moving.
@@beeble2003 Correct! As speed increases, the load which the diesel and traction alternator can produce is reduced. An alternator feeding 4 motors can provide more power to each. This way higher speed can be sustained by a 4 axle. This is why high powered 4 axle power, like GP40/50/60 B30/36-7, B40-8, C430 used to be preferred in time sensitive service. With PSR this thought has largely gone away. More effort is put into high tractive effort and maximum tonnage.
Thanks for the insights. I recall chatting with my dad about his work as an engineer 'back in the day' soon after I'd gotten hired by an airline. I realized that the locomotives he was running weighed roughly the same as a fully-loaded DC8 (for example). Then, added to that, was a 'few' more pounds of train running behind. His job was more about managing the the momentum of mass where the airline pilot's job was more about handing the momentum associated with speed. Similar in many ways - all about energy management (i.e you'd better be planning well ahead all the time). Cheers!
I think we are about the same age. When I was in college, back in the late 80s, I had to take a business strategy class which studied 4 different companies. I really only remember two of them. One was Harley-Davidson and the other was CSX (both of which, at the time, seemed to have their strategic plans in order). It's really great to hear the perspective from your career. Makes you understand a business more when you learn more about the actual "hands-on" aspects. Way too many C-level and above managers forget this.
Local shortline in my area pulls cement trains up a mountain. They commonly used all 7 of their GP38-2's on a single train. Sometimes they would have to split the train in half to make it up the mountain. Now they have 4 SD45's rebuilt to SD40-2 specs and kept 3 GP38-2's. Personally I loved the sound of those non turbocharged GP's.
Sounds like you have Maryland Midland close by... I love that they have the Sd45 carbodies with Sd40-2 guts. But it makes me mad they lost their Corporate identity
Grew up on Long Island. We had Alco C420s and later on in 75-76, GP-38-2s pulling commuter trains. Most were replaced in the 90s but there still some pulling freight on LI today. Real work horses.
DJ….this was AWESOME….At my age I never believed I could ever really run a train like you have…this video put me as close as I will ever come…great presentation and your delivery was great as usual!…hope all else is well.
I had an N scale train set way back when and just started getting back into it. I'm truly enjoying watching your videos, especially the shots taken with the drone. Those are going to be huge help with figuring out my layout.
Just a comment from a purely electrical engineer point of view, the cow-calf, mother and slug, master slave, whatever you want to call it.... What DJ was trying to convey was that for lower speed applications, yards movements, locals, and other operations where you're not really moving a high speed, but you need traction aka pulling power to get the train moving, the full capacity of any one diesel locomotive has more HP than it can actually put to the ground for say 80% of the trains it will pull at like less than 20 mph... so, you can save fuel by running just one motor, and fully utilizing that power spread over two locomotives worth of traction motors vs 2 engines running and only getting to half or 2/3 power. Also, 2 GP units has 8 powered axles, which is actually 2 more than a single SD locomotive with the SAME diesel engine powering it all. Arguably, the 2 extra axles of pulling power actually would pull better than a SD40-2 with the 3000 HP engine when compared to a mother slug with a GP40 (with the same 3000 HP engine) on the same train. Ok, so why not do all engines like this? Well, it comes down to speed. Just like in cars, more HP equates to higher top end speed. From a stop, a Ford Mustang will make just as much power before spinning the wheels in first gear as a Focus will before you smoke the tires... the difference is which one will have the higher top speed and get there quicker. Hence why for mainline use when you're not starting and stopping (aka highway running) you can carry more speed to get your freight to its destination more quickly. That's why your mainline engines are higher HP, and each one is powered. Hope that makes some sense for you guys. Oh, one other thing... the 4 axle locomotives will also typically take worse track conditions, tighter radius curves, and shorter switches better than their road unit counterparts. Think of it like maneuvering a little toyota truck in a parking lot versus a quad cab with an 8 foot bed...
Wow, I just finished part 1, and the information you’ve provided about engine / power selection - based on your experience as a RR engineer - is a game changer for me as I think about HO motive power for my small shelf switching layout. Thanks so much 😊
Very informative video dj!! I have been a railfan for many years,my wife says railroading is in my blood lol. I grew up by ATSF tracks in So-Cal then when I moved to Northern California,I lived really close to SP lines and then the WP was about 25 minutes away in another town. I had,and do have quite a few favorite engines. I like a few GP's and switchers but a lot of SD stuff,like the SD 9,40 snoot nose,40-T2,45-T2,50 and 60. Thanks again for another great video
I liked the Geep 40-2 and the slug. You got a SD 40-2 with two extra powered axles equivalent. They did fine pulling coal drags on the main line. Plus, the slugs cab was quite if that was in the lead. When they first came out they had Pacesetter controls that allowed you to load a coal train at a set speed. All time favorite was the SD 50, I liked the Doppler radar it used for wheel slip. Articles in magazines gave them a bad name. All I can say is,done pulled a many coal train out of Clifton Forge with just a single SD 50.
I've got a very different experience down here as a ground guy in the south. Our yard loco is a gevo and we get pissed if they give us a single 4 axle. Now the days I've had one of those 4 axle rebuilds, a slug set and my gevo in the yard. Fun fun fun.
ANOTHER GOOD VIDEO THANK YOU DJ THIS IS BECOMEING THE BEST TH-cam CHANEL TO WATCH FOR GOOD INFORMATION ON THIS SUBJECT I APPRECIATE IT AND YOU HAVE A GOOD DAY TODAY JIM KAMMERER OF PHILADELPHIA PA 👌 😀 😊
I did not know that about slugs, I thought they had engines in them as well. not cement. very cool. Love this stuff from you, always learning something
On the UP , the roundhouse doesn't care what "you prefer" ! You get them how they came in on our Haulers. Maybe you'll get a radio, maybe you won't. Maybe you get operating PTC, maybe you won't. It doesn't matter to them. As long as the leaders loads and has a radio. Maybe .. Just maybe they cleaned the toilet, if we're lucky.
The Chessie System, for the most part, did not believe in 6 axle engines. They bought GP35's 38's and 40's by the hundreds. The merger of Chessie and Seaboard to from CSX happened Nov. 1, 1980. At one time the mother-slug combination also used the fuel tank on the slug to supplement the fuel tank on the mother and thus extend the time between refueling - that experiment failed. A similar experiment was tried on the Seminole Coal Train that operated between Chattachoochee, FL and the power plant at Bostwick, FL. In the early 90's power for the train was two GE Dash-8's, a 30000 gallon tank car was connected between the units and was configured to supply both - with this configuration the train was refueled weekly not every other trip - it was stopped when it was determined that the tank car could not withstand the repeated buff and draft forces it was experiencing in the service.
Conrail also had tones of GP-38's that they ran on the main line up in Canada. why I fell in love with them as a kid, 4 or 5 GP-38 pulling over 100 cars. see this about 25 times a day. In St Thomas Ontario we had the Conrail main engine shops and Chessie had their main engine shop as well. their yard was full of GP-9
Cool video DJ! The BNSF GPs used here on the Thayer Subdivision can range from from as old as GP7u (of which one is the car repair shop switcher at Harvard Yard in Marion, Arkansas) and GP30s to more modern ex Santa Fe GP60Ms and B40-8Ws! Probably the most unique group of these 4 axle locomotives is the GP25s, these units are rebuilds from several different EMD models most commonly, the GP50, GP40X and GP35 body styles ( although there are also GP35s and GP30s that have been reclassified as GP39-3s).
Hi DJ, Great video. Not sure if CSX has any, but in Conway we have Super Hump sets that are one SD40-2 that powers (2) 6 axle slugs. Also our Conway shop switcher is a former Reading Railroad SW1001, pretty rare and neat little shifter. Although with that short wheel base she's a little bit of a rough rider especially when going through the frog of a switch. I had the same experience the first time I moved a mother slug set from the slug end. You can hear the switchgear and even the traction motor noise, it's like what the heck because you don't have that 16 cylinder sound system in the back room 😂 Cheers, Rich S.
I was in my early teens when we went to Punxsy for a weekend to visit Dad’s sister & family. My uncle was working the yard send cars to various tracks building train for mainline runs. This was a 60s B&O diesel locomotive and I had a chance to go up in the cab! There was a small door (or 2) in the cab that led to the engine. It was where I learned diesel locomotives were electric and the hum inside that locomotive was loud. I had expected to see this huge motor, like in a car or truck, but not this big humming generator, if that’s the correct term.
I used to go up to Willard to watch them hump cars. One time I was down by the roundhouse when a hogger was trying out a rebuilt GP40-2. On the spare track beside the roundhouse he would gun the engine to the 8th notch and run it up towards the west hump, stop, and come back as fast. He did this for over an hour and I had to get home. I always felt the EMD's were quicker on the throttle than the GE's. This was all back in the 80's.
Nice video man! Only 2 locos on my layout - GE B23-7's, tail to tail consist, all day every day just like my prototype. As for the bathroom - That's what the woods are for😆Take care - Bill
Love your video's I have a few where I put you in the CSX Engineers seat as we fly down the main line just type CSX Engineer Burt narrates fantastic run in search box!
I saw one yesterday, I'll watch more. Here is the only one I had recorded back with Brady Fry and also Jimmy Warren.th-cam.com/video/B6vnodCGZkY/w-d-xo.html
Great video and tutorial of the GP locomotives and the functions of them! As you know I'm a fan of the GP's and the EMD MP15AC. You're very knowledgeable and of course you would be being an Engineer. I'm also glad you explained how the Slug operates. Always look forward to seeing your videos. Thanks again DJ for sharing your videos with us along with your PRICELESS time and effort! Cheers from Delmar, Delaware.
Hello sir, happy holidays. I'm just curious, I'm not really a die-hard rail fan per say but, why were most END's now phased out? I can recall hearing the distinctive sounds of EMD engines back in the day. Seems like nowadays you don't hear that particular sound anymore. The new locos are much more quieter. I guess I can understand that, of course, technology plays a big part on the railroad industry. I just happened to stumble on your channel. Very interesting, thanks👊👍
The NS crews here don't like the mother/slug sets. There is only one or two assigned to Buffalo, one of which is the GP33ECO/RP-M4C duo permanently assigned to Buffalo. At the RSR interchange the cars usually go on a siding that has a quite significant grade, and the mother/slug set just doesn't have the umph to shove a sizable train up that hill. Give them SD40-2s, SD40Es, SD60Es or plain GPs and they love it, but those slugs nope.
Again 🎩🎩off to ya Great stuff,Love your Comments about 40-3 a pain ! I Service AMF 82/70 and 82/90 Pinsetters, with all the new regulations the 8290s are a pain because of safety protocols ! Thanks again 🚂🚂
Hey DJ!! Thank you for the presentation and information. Very helpful knowledge especially for ops sessions on my layout. Thanks for sharing and have a good day. Happy modeling!! -Jason
A quick question - - I have been wondering if you perform a LAB test on the train similar to a tractor trailer before you move? LAB stands for leaks (checking for air leaks), alarms (low air alarm), and buttons (making sure the emergency brake engages). As a cdl driver I have to perform the labs test before I role. Just wondering if for you it's the same. Thanks! Love your videos. Steve
Depending on the type of operation, there are different classes of tests that need to be done, and in some cases we don't have to perform any tests at all. Some tests require that all the brakes on every car set up, remain set for a certain length of time, and all release. Some tests only check that the brakes set up, but not release. There are separate types of tests that must be done on locomotives and not cars, and all of the tests required are determined by when you do them. If I'm just swapping crews on a road train that's already been air tested, I don't have to do any tests. Just get on and go. But if I pickup cars and/or locomotives, or setout cars enroute, there are air and equipment safety tests to do.
Let me ask you a “crystal ball” question…. Buddy of mine and I have discussed this before. Typically RRs seem to downgrade locomotives to yard/local duty. With the four axles getting older and retired and mostly new engines being built as six axles at what point will they have to put four axle locomotives back into production? I don’t see them using the big Evos as you called them in yard or local duty. So what is the fix? Thx as always for the content sir.
I'm not DJ and he may have a different answer, but honestly the 4 axles can be rebuilt until the end of time. On the railroad where I work and it maybe the same with CSX, we have 4 axle EMD's that were built in 1968. All the parts are renewable from the traction motors, to the switchgear, rad fans, main generator and diesel engine. And all the parts are still available from EMD and other suppliers. On a side note, parts are big business and as long as the railroads need parts for 4 axle locomotives, they'll remain available. So you are correct and just my opinion but the largest locomotive you'll ever see on a local or yard service is a SD40-2, otherwise that type of service will remain the domain of the 4 axle EMD's. Sadly the 4 axle GE's were very slippery, an issue GE has since correct with it's 6 axle power. EMD hit it out of the park early with their IDAC Wheel Slip system introduced in the late 1960's and then they added to what they achieved with IDAC with the introduction of their "Super Series" Wheel Slip system, but that's a discussion way beyond this video. Sorry for being so long winded but I hope I answered your question? Cheers, Rich S.
@@RWSBaden excellent answer, thank you. I guess we will see if the market dictates new models. Rebuilts available or not there might come a time when the supply available outstrips the demand and new ones needed or the bean counters can’t justify an expense on something over 60 years old…..
CP rebuilt their GP9 fleet into GP20eco. BNSF had the GP28, with modern bodies and -2, which were rebuilt from GP9, the GP39 program rebuilt from GP30/35, and they had many rebuilt GP38s too.
HI DJ @@djstrains If I was to make a guess, Any new 4 axles would come from a third party supplier like the National Railway Equipment, Brookville, Railpower Technologies or MotivePower. My reasoning is based on what has happened over the past 40 years in the locomotive market. During the 1970's, a railroad could purchase a GP38-2, SD38-2, GP39 GP40-2, SD40-2 and SD45-2. Move forward 10 years and your choices from EMD were a GP50 and SD50, which ended up with 645 diesel engine trouble. Next came the GP60 and SD60. Yes there were a few odd ball test beds during the time that were only purchased by a few railroads like the Southerns GP49's and GP59's. Move to the 90's and what was the locomotive choices, SD70 and variants but with no 4 axle offered. Today you have two choices from EMD, SD70Ace or they will rebuild one of your older SD70's from DC traction motors to AC traction motors. Just the way I see it, but I don't see GE or EMD getting back into the 4 axle market, unless you consider EMD's rebuild programs will they'll take a older locomotive like a GP38 and convert it into a ECO locomotive with a Caterpillar 12 cylinder diesel engine and updated electronics. Sorry for the long answer DJ, but that is how I see the locomotive market over the next 20 years. Cheers Rich S.
I personally dont have any footage. Also, I did not get the opportunity to drive it, and the security around it makes it challenging. The management wont even talk to us peons.
In the movie Unstoppable if you have seen it what are the inconsistencies that you as a professional would see immediately I have one from the very beginning when Denzel & Chris Pine are walking to their assigned locomotive for the day they are stepping on the rails and I know that is a big No No !!!! What do you think about that movie D.J.
I personally love the smell of diesel exhaust. DJ have you ever had to run a big engine long hood forward? By me i get a coal train that serves a power plant in my city. There have been many cases lately where the loads come in with all engines facing north and when the empties leave they have to run long hood forward. I cant imagine how horrible it must be to see doing that.
Yes, on many occasions. Problem is many big engines dont have rear ditch lights. That means only 20 mph over a road crossing which may make for a very long day.
@@djstrains on some occasions the crew had brought portable ditch lights. Union Pacific doesn't have rear ditch lights on their big engines but I thought most CSX engines have ditch lights on both sides. Maybe im thinking of Norfolk Southern.
It's like trying to compare a 2022 Ferrari with a 1970 Volkswagen Beetle. Which do you think they are going to invest this technology into? Even when we had manned helpers we used huge 6 axle engines. I was hoping this video explained what these 4 axle engines are used for.
@@djstrains It's also like comparing my truck to a bigger one. I have a 2020 F150 and compare that to the same year for the Super Duty. My payload and towing capacity is lower than that of let's say an F250 or even an F350 SRW or even a Dually
@@williamh.jarvis6795 very good actually. It's an old TM900. The sanders have been removed but it still pulls good. Don't get much trackage because only have about 200 yards to work on. But even with out sanders I'm pulling on fully loaded hoppers up a grade on a curve. It's awesome.
Once again DJ, great video. I have a question on the topic of Engines. Maybe you can answer in one of these series of videos, but what does the “-2” on like a GP40-2 or SD40-2?
nice explaination, you've caught my interest.i live 500 ft away from a NS main line.i can hear differences in engines as they pass.the southbound coal trains coming out of pa.will viberate the house windows.& DPU's at mid & tail.judging by the vibrations & sound the DPU's are pushing harder than the leading engines are pulling.& some even scream like a banshee that is louder than the diesel.i assumed an extremely high output generator under intense electrical load? thanks.
You are very wise! Yes, the auto pilot feature sometimes has the dpu shoving while lead is in dynamic braking! I hate this, makes me feel like we gonna pop a car off on a curve!
Great question. Its automatic. But what I never mentioned is that if engines are radically different, we can feel one pushing or pulling the other sometimes.
Another banger DJ! 🎉 I wonder if your familiar with any of the railroad simulators such as Train Sim World? It would be nice to see a hands on approach to how you might operate a locomotive. Can’t wait for the six axle video. Thanks for all your hard work!
Not that I would be a candidate to become an engineer but it has always fascinated me thinking about it. I am 51 and just became type 1 diabetic (or type 1.5 for anyone who knows) only 4 years ago. Do railroads have restrictions with hiring regarding type 1 diabetics?
Not sure why TH-cam keeps unsubscribing me from your channel. Anyway thanks for the info, never felt right adding my GP to the front of a consist any of my long distance trains. I knew there was a reason lol
You know what? I think i understand the mother slug concept. The slug provides even more traction without needing another diesel engine. You're getting twice as many traction motors with just one diesel engine
Conrail used GP unit's everywhere didn't matter in the 70's & 80's 9:15 Best way to Explain it is the mother & Slug Unit and why Concrete slabs are mostly found under the hoods of slugs is because the missing necessary weight of the primary Engine that has been removed, a Single Locomotive has an enough Voltage Power and Traction effort to pull more than 80 cars by themselves but needs more weight and it's power spread out as it can't because they will honestly slip when trying to do so but if it has another unit then it's stretching out the Locomotives Mass Volume of Traction effort by adding another locomotive or Slug ensures maximum power and torque of the Mother or and of Mainline Train Unit's when pushing or Pulling, mostly used in Yards on Humps as this is the Reason why this is possible with the help of a different gears on the Traction Motors of the Slug makes things come alive plus all Mother Units mated to Slugs top speed is restricted to 15mph when using them as the torque is too great for a top speed to handle. A flip of a switch in the mother unit the engineer can shut the power to the slug's traction motors off making the mother unit smooth riding and move faster when not coupled to said freight cars as this is what was done when I worked for Conrail may have changed now a days but not by much.
DJ, great video. Great explanation of rimpull (tractive effort) I will have to plagiarize when I teach NUBE Civil Engineers. Also, I think CSX has 1 or 2 of the MP 15s in Baldwin, Florida. At least something that looks a whole lot like the pic. Just a noisy diesel that they use to cut and build trains, fully remote. The conductor called it a "Butt Head". Again, great post, truly enjoy the videos and reading the comments. Looking forward to part 2.
I know there's one, the crews treat it like the short straw when it comes to power. I remember I was getting off a transfer job up there and having to wait for a track to be shoved back in before I crossed the yard from my motor. I see a cut creeping by consisting well cars, loaded ballast cars, then a lone MP15 absolutely screaming as it tried to move the train. I was riding with some old head engineer who just grunted and said "And they wonder why their s**t breaks" under his breath
the biggest difference between 4 and 6 axles is tractive effort. 4 axle locomotives hit their high water mark with the GP60 or the B40-8. They were popular on hot trains, like Intermodal where the high horsepower could perform better with 4 axles. Hot trains always had 4 axle units and several of them so they could run at speed and accelerate quickly, also would still make good time if they lost a unit on the run. With the closing of the GP era, Horsepower had already reached 900hp per axle and was not able to hold the rail at lower speeds using that much power, you just couldnt stick that much power to the rail with 4 axles. For the same reason you wouldnt want a lashup of GP60s on a coal drag, they would run fast if they ever made it up to speed but all that horsepower would be useless trying to start or pull a grade, the ammeter would be stuck in the red until you melted the traction motors 😂. If you spread the same power over 6 axles then you have much more thermal capacity and can hold a higher throttle position, putting that power to the rail.
I pinned this as top comment. You are welcome to add this kind of insight to any videos, it was well written and articulated.
@@djstrains thanks brother, just love sharing all things trains and your channel is one of the best sources for the entirety of the railroad topic. You cover it all DJ, Cheers Rob hope maybe someday to hear one of those air starters. The big old C series Alcos had them, the sound neat 😁😁
The OP isn't entirely accurate. The key point is that power equals force times speed. A four-axle unit can't exert a lot of force on the rail. Not particularly because of the limits of traction motors but because of the limits of adhesion. If you compare a GP60 and an SD60, both have 3800hp, and the SD60 is about 50% heavier and has 50% more axles. Both have the same weight on each axle, which means that both have the same friction (grip) per axle. But, overall, there's 50% more friction between an SD60 and the rails than a GP60. And, by Newton's third law, that means the SD60 can exert 50% more force on the train.
It's this increased ability to apply force to the rails (aka, tractive effort) that allows an SD60 to get a heavy train moving, or to haul it uphill. GP60s can do the same thing, except that you need 50% more of them. If your train needs two SD60s to get it moving, it would need three GP60s, even though the GP60s would have 11400hp vs the 7600hp of the two SD60s. If you try to put all 3800hp through the four axles of a GP60 at low speed, the force will exceed the friction between the wheels and the rails, and the wheels will spin. (Power equals force times speed, so high power and low speed means high force.) Indeed, for this reason, many four-axle locomotives have a control system that limits the power at low speed to about the same power per axle as a six-axle unit. This is why slugs are a thing -- instead of being unable to use the extra power at low speed, you put it into another locomotive's traction motors.
At speed, putting all that power through four axles is fine, because the force generated is relatively low -- but still enough to keep the train moving. A six-axle unit could do just as well at those speeds, but there's no point hauling all that extra weight around. At least, that used to be the philosophy. Now they figure they may as well just use six-axle units for everything and save the inconvenience of having multiple types of locomotive. And you can't use a slug at high speed, because the mother-slug pair doesn't have enough power to generate enough force at high speed to keep the train moving.
@@beeble2003 Sincerely appreciated for the thorough explanation!
@@beeble2003 Correct! As speed increases, the load which the diesel and traction alternator can produce is reduced.
An alternator feeding 4 motors can provide more power to each. This way higher speed can be sustained by a 4 axle. This is why high powered 4 axle power, like GP40/50/60 B30/36-7, B40-8, C430 used to be preferred in time sensitive service.
With PSR this thought has largely gone away. More effort is put into high tractive effort and maximum tonnage.
Thanks for the insights. I recall chatting with my dad about his work as an engineer 'back in the day' soon after I'd gotten hired by an airline. I realized that the locomotives he was running weighed roughly the same as a fully-loaded DC8 (for example). Then, added to that, was a 'few' more pounds of train running behind. His job was more about managing the the momentum of mass where the airline pilot's job was more about handing the momentum associated with speed. Similar in many ways - all about energy management (i.e you'd better be planning well ahead all the time). Cheers!
we are so similar!!!
As a model railroader I love videos like this. The more you can tell about the controls and “driving” the better.
I have a lot of videos in my "life as an engineer" playlist that you might enjoy. More to come also.
I think we are about the same age. When I was in college, back in the late 80s, I had to take a business strategy class which studied 4 different companies. I really only remember two of them. One was Harley-Davidson and the other was CSX (both of which, at the time, seemed to have their strategic plans in order). It's really great to hear the perspective from your career. Makes you understand a business more when you learn more about the actual "hands-on" aspects. Way too many C-level and above managers forget this.
Been in the hobby 60 yrs. I learn something new in all your videos. Great job.
Local shortline in my area pulls cement trains up a mountain. They commonly used all 7 of their GP38-2's on a single train. Sometimes they would have to split the train in half to make it up the mountain. Now they have 4 SD45's rebuilt to SD40-2 specs and kept 3 GP38-2's. Personally I loved the sound of those non turbocharged GP's.
Sounds like you have Maryland Midland close by... I love that they have the Sd45 carbodies with Sd40-2 guts. But it makes me mad they lost their Corporate identity
Grew up on Long Island. We had Alco C420s and later on in 75-76, GP-38-2s pulling commuter trains. Most were replaced in the 90s but there still some pulling freight on LI today. Real work horses.
My uncle was an engineer there. He liked the GP38-2 best. I’ve logged thousands of miles on GP38s to. My uncle was right about their superiority.
DJ….this was AWESOME….At my age I never believed I could ever really run a train like you have…this video put me as close as I will ever come…great presentation and your delivery was great as usual!…hope all else is well.
This made my day!!
We have a CSxX train that splits our farm just north of Delaware, Ohio. I always wave at the engineers.
Absolutely amazing thanks for explaining this to non-railroad person brilliant.
Glad it was helpful!
I know that slugs have traction motors but it’s basically almost similar to a cab car that would be found on commuter railroad such as Metro North
I had an N scale train set way back when and just started getting back into it. I'm truly enjoying watching your videos, especially the shots taken with the drone. Those are going to be huge help with figuring out my layout.
That is awesome!
Just a comment from a purely electrical engineer point of view, the cow-calf, mother and slug, master slave, whatever you want to call it.... What DJ was trying to convey was that for lower speed applications, yards movements, locals, and other operations where you're not really moving a high speed, but you need traction aka pulling power to get the train moving, the full capacity of any one diesel locomotive has more HP than it can actually put to the ground for say 80% of the trains it will pull at like less than 20 mph... so, you can save fuel by running just one motor, and fully utilizing that power spread over two locomotives worth of traction motors vs 2 engines running and only getting to half or 2/3 power. Also, 2 GP units has 8 powered axles, which is actually 2 more than a single SD locomotive with the SAME diesel engine powering it all. Arguably, the 2 extra axles of pulling power actually would pull better than a SD40-2 with the 3000 HP engine when compared to a mother slug with a GP40 (with the same 3000 HP engine) on the same train.
Ok, so why not do all engines like this?
Well, it comes down to speed. Just like in cars, more HP equates to higher top end speed. From a stop, a Ford Mustang will make just as much power before spinning the wheels in first gear as a Focus will before you smoke the tires... the difference is which one will have the higher top speed and get there quicker. Hence why for mainline use when you're not starting and stopping (aka highway running) you can carry more speed to get your freight to its destination more quickly. That's why your mainline engines are higher HP, and each one is powered.
Hope that makes some sense for you guys.
Oh, one other thing... the 4 axle locomotives will also typically take worse track conditions, tighter radius curves, and shorter switches better than their road unit counterparts. Think of it like maneuvering a little toyota truck in a parking lot versus a quad cab with an 8 foot bed...
I sincerely appreciate your thorough explanation! Thanks!
@@djstrains I'm trying to offset the bad foamers! Lol!
Wow, I just finished part 1, and the information you’ve provided about engine / power selection - based on your experience as a RR engineer - is a game changer for me as I think about HO motive power for my small shelf switching layout.
Thanks so much 😊
Thank you so very much! I love this video and think you will also: th-cam.com/video/3yJWPmugPIk/w-d-xo.htmlsi=-XUGbWHnmG7VqlNT
@@djstrains You're welcome, and that video is fantastic, because as you said, most of us modelers will never see most of this stuff.
Always good to hear the perspective of one who sits at the controls. Thanks for the explanation.
Very informative video dj!! I have been a railfan for many years,my wife says railroading is in my blood lol. I grew up by ATSF tracks in So-Cal then when I moved to Northern California,I lived really close to SP lines and then the WP was about 25 minutes away in another town. I had,and do have quite a few favorite engines. I like a few GP's and switchers but a lot of SD stuff,like the SD 9,40 snoot nose,40-T2,45-T2,50 and 60. Thanks again for another great video
I liked the Geep 40-2 and the slug. You got a SD 40-2 with two extra powered axles equivalent. They did fine pulling coal drags on the main line. Plus, the slugs cab was quite if that was in the lead. When they first came out they had Pacesetter controls that allowed you to load a coal train at a set speed. All time favorite was the SD 50, I liked the Doppler radar it used for wheel slip. Articles in magazines gave them a bad name. All I can say is,done pulled a many coal train out of Clifton Forge with just a single SD 50.
Thanks for sharing your vast knowledge and making is accessible to everyone. Hobby needs more guys like you!
I appreciate that!
Would have never guessed they filled those with cement 🤯 Makes sense though. Cool videos brotha 👏👏
They Use to call that Mother/slug setup Cow & Calf power
This is awesome, I was just trying to figure this out the other day and was getting overwhelmed by pages of discussion on forums and stuff.
Thank you for this informative video.
I remember we had an old Model Railroader magazine that talked about modeling Seaboard mother-slug units.
This was a great presentation! Thanks, DJ!
I've got a very different experience down here as a ground guy in the south. Our yard loco is a gevo and we get pissed if they give us a single 4 axle. Now the days I've had one of those 4 axle rebuilds, a slug set and my gevo in the yard. Fun fun fun.
ANOTHER GOOD VIDEO THANK YOU DJ THIS IS BECOMEING THE BEST TH-cam CHANEL TO WATCH FOR GOOD INFORMATION ON THIS SUBJECT I APPRECIATE IT AND YOU HAVE A GOOD DAY TODAY JIM KAMMERER OF PHILADELPHIA PA 👌 😀 😊
I appreciate that
I did not know that about slugs, I thought they had engines in them as well. not cement. very cool. Love this stuff from you, always learning something
Some do have engines. In my yard we have one proper slug without a diesel prime mover, and 3 that do.
Increasing that normal force increases the frictional force with a constant kinetic friction coefficient.
Awesome update DJ .Liked it very much!! Well done. Cheers DD.
That's the great part about the hobby sharing ideas and learning new ideas from other people to improve our Channel.
On the UP , the roundhouse doesn't care what "you prefer" ! You get them how they came in on our Haulers. Maybe you'll get a radio, maybe you won't. Maybe you get operating PTC, maybe you won't. It doesn't matter to them. As long as the leaders loads and has a radio. Maybe .. Just maybe they cleaned the toilet, if we're lucky.
OR MAYBE WE FILL THE TOILET WITHA BAG OF ICE TO KEEP THE SMELL DOWN.
The Chessie System, for the most part, did not believe in 6 axle engines. They bought GP35's 38's and 40's by the hundreds. The merger of Chessie and Seaboard to from CSX happened Nov. 1, 1980. At one time the mother-slug combination also used the fuel tank on the slug to supplement the fuel tank on the mother and thus extend the time between refueling - that experiment failed. A similar experiment was tried on the Seminole Coal Train that operated between Chattachoochee, FL and the power plant at Bostwick, FL. In the early 90's power for the train was two GE Dash-8's, a 30000 gallon tank car was connected between the units and was configured to supply both - with this configuration the train was refueled weekly not every other trip - it was stopped when it was determined that the tank car could not withstand the repeated buff and draft forces it was experiencing in the service.
THIS IS SUCH VALUABLE INFORMATION!!! Thanks for sharing!!
Conrail also had tones of GP-38's that they ran on the main line up in Canada. why I fell in love with them as a kid, 4 or 5 GP-38 pulling over 100 cars. see this about 25 times a day. In St Thomas Ontario we had the Conrail main engine shops and Chessie had their main engine shop as well. their yard was full of GP-9
Cool video DJ! The BNSF GPs used here on the Thayer Subdivision can range from from as old as GP7u (of which one is the car repair shop switcher at Harvard Yard in Marion, Arkansas) and GP30s to more modern ex Santa Fe GP60Ms and B40-8Ws! Probably the most unique group of these 4 axle locomotives is the GP25s, these units are rebuilds from several different EMD models most commonly, the GP50, GP40X and GP35 body styles ( although there are also GP35s and GP30s that have been reclassified as GP39-3s).
Great video DJ. You answered a lot of mystery questions. Thanks.
Glad to help
Great info on US locos ! Hi from Europe 👋🏿
Hello there!
FEC Railway was a 4 axle GP railroad for about 35 years until they purchased 22 ex UP SD40-2s which was their first six axle power in 2002.
How many have the derailed in yard or customer facilities on less than perfect track?
Hi DJ, Great video. Not sure if CSX has any, but in Conway we have Super Hump sets that are one SD40-2 that powers (2) 6 axle slugs. Also our Conway shop switcher is a former Reading Railroad SW1001, pretty rare and neat little shifter. Although with that short wheel base she's a little bit of a rough rider especially when going through the frog of a switch. I had the same experience the first time I moved a mother slug set from the slug end. You can hear the switchgear and even the traction motor noise, it's like what the heck because you don't have that 16 cylinder sound system in the back room 😂 Cheers, Rich S.
Love it!
Great video, as always, thank you for sharing and putting into terminology that non railroaders can understand.
You bet!
I love the footage you used from our day at Strasburg.
DJ thanks again for the good information I always enjoy your videos as always please work safe
I was in my early teens when we went to Punxsy for a weekend to visit Dad’s sister & family. My uncle was working the yard send cars to various tracks building train for mainline runs. This was a 60s B&O diesel locomotive and I had a chance to go up in the cab! There was a small door (or 2) in the cab that led to the engine. It was where I learned diesel locomotives were electric and the hum inside that locomotive was loud. I had expected to see this huge motor, like in a car or truck, but not this big humming generator, if that’s the correct term.
Well done and highly informative. I look forward to the next chapter.
I used to go up to Willard to watch them hump cars. One time I was down by the roundhouse when a hogger was trying out a rebuilt GP40-2. On the spare track beside the roundhouse he would gun the engine to the 8th notch and run it up towards the west hump, stop, and come back as fast. He did this for over an hour and I had to get home. I always felt the EMD's were quicker on the throttle than the GE's. This was all back in the 80's.
Nice video man! Only 2 locos on my layout - GE B23-7's, tail to tail consist, all day every day just like my prototype. As for the bathroom - That's what the woods are for😆Take care - Bill
Another very nice video to enjoy. Thank you very much for sharing them with all of us. Have a nice rest of your day.
Thank you! You too!
@@djstrains Your welcome and thanks also.
Love your video's I have a few where I put you in the CSX Engineers seat as we fly down the main line just type CSX Engineer Burt narrates fantastic run in search box!
I saw one yesterday, I'll watch more. Here is the only one I had recorded back with Brady Fry and also Jimmy Warren.th-cam.com/video/B6vnodCGZkY/w-d-xo.html
Great video and tutorial of the GP locomotives and the functions of them! As you know I'm a fan of the GP's and the EMD MP15AC. You're very knowledgeable and of course you would be being an Engineer. I'm also glad you explained how the Slug operates. Always look forward to seeing your videos. Thanks again DJ for sharing your videos with us along with your PRICELESS time and effort! Cheers from Delmar, Delaware.
Thank you very much!
That was really informative. Thanks for sharing.
Great video DJ, love these layman videos for the great info👍👍👍
....I don't want to bash any company {{WABTEC}} but with the Dash Threes....
LOL Smooth!
Thanks for the info dude!
Thanks for the videos, how I viewed the difference between the Sd and Gp for example SD38 and GP38 same hp but more traction on Sd!👍
Hello sir, happy holidays. I'm just curious, I'm not really a die-hard rail fan per say but, why were most END's now phased out? I can recall hearing the distinctive sounds of EMD engines back in the day. Seems like nowadays you don't hear that particular sound anymore. The new locos are much more quieter. I guess I can understand that, of course, technology plays a big part on the railroad industry. I just happened to stumble on your channel. Very interesting, thanks👊👍
New video at noon tomorrow you may like
My favorite loco to run was the GP39-2.
Very helpful. Thank you, DJ.
The NS crews here don't like the mother/slug sets. There is only one or two assigned to Buffalo, one of which is the GP33ECO/RP-M4C duo permanently assigned to Buffalo. At the RSR interchange the cars usually go on a siding that has a quite significant grade, and the mother/slug set just doesn't have the umph to shove a sizable train up that hill. Give them SD40-2s, SD40Es, SD60Es or plain GPs and they love it, but those slugs nope.
Great Video. At Oak Point I've seen a couple of Gensets that CSX use for switching and going local.
gensets are garbage, lol.
Again 🎩🎩off to ya Great stuff,Love your Comments about 40-3 a pain ! I Service AMF 82/70 and 82/90 Pinsetters, with all the new regulations the 8290s are a pain because of safety protocols ! Thanks again 🚂🚂
Man you have given me so much insight
GP38-2 are the best for yard work
Hey DJ awesome insightful content ... love it!
More to come.
Hey DJ!! Thank you for the presentation and information. Very helpful knowledge especially for ops sessions on my layout. Thanks for sharing and have a good day. Happy modeling!! -Jason
Glad it was helpful!
Damn, I learned something new today, thanks DJ
Hi DJ. Great video as always. Thanks for sharing this with us!
Glad you enjoyed it
A quick question - - I have been wondering if you perform a LAB test on the train similar to a tractor trailer before you move? LAB stands for leaks (checking for air leaks), alarms (low air alarm), and buttons (making sure the emergency brake engages). As a cdl driver I have to perform the labs test before I role. Just wondering if for you it's the same. Thanks! Love your videos. Steve
also a "Depature test" on our positive train control.
Depending on the type of operation, there are different classes of tests that need to be done, and in some cases we don't have to perform any tests at all. Some tests require that all the brakes on every car set up, remain set for a certain length of time, and all release. Some tests only check that the brakes set up, but not release. There are separate types of tests that must be done on locomotives and not cars, and all of the tests required are determined by when you do them. If I'm just swapping crews on a road train that's already been air tested, I don't have to do any tests. Just get on and go. But if I pickup cars and/or locomotives, or setout cars enroute, there are air and equipment safety tests to do.
Thanks DJ. Awesome information.
Let me ask you a “crystal ball” question….
Buddy of mine and I have discussed this before. Typically RRs seem to downgrade locomotives to yard/local duty. With the four axles getting older and retired and mostly new engines being built as six axles at what point will they have to put four axle locomotives back into production? I don’t see them using the big Evos as you called them in yard or local duty. So what is the fix?
Thx as always for the content sir.
I'm not DJ and he may have a different answer, but honestly the 4 axles can be rebuilt until the end of time. On the railroad where I work and it maybe the same with CSX, we have 4 axle EMD's that were built in 1968. All the parts are renewable from the traction motors, to the switchgear, rad fans, main generator and diesel engine. And all the parts are still available from EMD and other suppliers. On a side note, parts are big business and as long as the railroads need parts for 4 axle locomotives, they'll remain available. So you are correct and just my opinion but the largest locomotive you'll ever see on a local or yard service is a SD40-2, otherwise that type of service will remain the domain of the 4 axle EMD's. Sadly the 4 axle GE's were very slippery, an issue GE has since correct with it's 6 axle power. EMD hit it out of the park early with their IDAC Wheel Slip system introduced in the late 1960's and then they added to what they achieved with IDAC with the introduction of their "Super Series" Wheel Slip system, but that's a discussion way beyond this video. Sorry for being so long winded but I hope I answered your question? Cheers, Rich S.
@@RWSBaden excellent answer, thank you.
I guess we will see if the market dictates new models. Rebuilts available or not there might come a time when the supply available outstrips the demand and new ones needed or the bean counters can’t justify an expense on something over 60 years old…..
CP rebuilt their GP9 fleet into GP20eco. BNSF had the GP28, with modern bodies and -2, which were rebuilt from GP9, the GP39 program rebuilt from GP30/35, and they had many rebuilt GP38s too.
million dollar question that I also want an answer.
HI DJ @@djstrains If I was to make a guess, Any new 4 axles would come from a third party supplier like the National Railway Equipment, Brookville, Railpower Technologies or MotivePower. My reasoning is based on what has happened over the past 40 years in the locomotive market. During the 1970's, a railroad could purchase a GP38-2, SD38-2, GP39 GP40-2, SD40-2 and SD45-2. Move forward 10 years and your choices from EMD were a GP50 and SD50, which ended up with 645 diesel engine trouble. Next came the GP60 and SD60. Yes there were a few odd ball test beds during the time that were only purchased by a few railroads like the Southerns GP49's and GP59's. Move to the 90's and what was the locomotive choices, SD70 and variants but with no 4 axle offered. Today you have two choices from EMD, SD70Ace or they will rebuild one of your older SD70's from DC traction motors to AC traction motors. Just the way I see it, but I don't see GE or EMD getting back into the 4 axle market, unless you consider EMD's rebuild programs will they'll take a older locomotive like a GP38 and convert it into a ECO locomotive with a Caterpillar 12 cylinder diesel engine and updated electronics. Sorry for the long answer DJ, but that is how I see the locomotive market over the next 20 years. Cheers Rich S.
Could you do a video on the csx1 train?
I personally dont have any footage. Also, I did not get the opportunity to drive it, and the security around it makes it challenging. The management wont even talk to us peons.
Dont know if you seen this. Pretty interesting at least for me. th-cam.com/video/4zZQtX6sh20/w-d-xo.html
In the movie Unstoppable if you have seen it what are the inconsistencies that you as a professional would see immediately I have one from the very beginning when Denzel & Chris Pine are walking to their assigned locomotive for the day they are stepping on the rails and I know that is a big No No !!!! What do you think about that movie D.J.
on my patreon site I made a review video. TH-cam wont let me play it because I used too much footage.
I personally love the smell of diesel exhaust. DJ have you ever had to run a big engine long hood forward? By me i get a coal train that serves a power plant in my city. There have been many cases lately where the loads come in with all engines facing north and when the empties leave they have to run long hood forward. I cant imagine how horrible it must be to see doing that.
Yes, on many occasions. Problem is many big engines dont have rear ditch lights. That means only 20 mph over a road crossing which may make for a very long day.
@@djstrains on some occasions the crew had brought portable ditch lights. Union Pacific doesn't have rear ditch lights on their big engines but I thought most CSX engines have ditch lights on both sides. Maybe im thinking of Norfolk Southern.
Very interesting topic, answered many questions. Thanks
Glad it was helpful!
DJ, why can’t GP’s be used for distributed power?
It's like trying to compare a 2022 Ferrari with a 1970 Volkswagen Beetle. Which do you think they are going to invest this technology into? Even when we had manned helpers we used huge 6 axle engines. I was hoping this video explained what these 4 axle engines are used for.
@@djstrains That makes sense - The GP’s just don’t have the tech. My local RR, a short line, uses mostly GP’s for power.
@@djstrains It's also like comparing my truck to a bigger one. I have a 2020 F150 and compare that to the same year for the Super Duty. My payload and towing capacity is lower than that of let's say an F250 or even an F350 SRW or even a Dually
Great series , very interesting ... Thx for posting ...
Glad you enjoyed it
They look cool always liked them
Great info!! Very informative. Thanks for sharing!! Stay Safe & God Bless!!!
You too!
Great video. All I get to drive is a trackmobile. 😭
hahahaha
How well does a "track-mobile" perform?
@@williamh.jarvis6795 very good actually. It's an old TM900. The sanders have been removed but it still pulls good. Don't get much trackage because only have about 200 yards to work on. But even with out sanders I'm pulling on fully loaded hoppers up a grade on a curve. It's awesome.
Awesome video and great information about your job
Glad you liked it!
Thanks I like trains.
I do too
Once again DJ, great video. I have a question on the topic of Engines. Maybe you can answer in one of these series of videos, but what does the “-2” on like a GP40-2 or SD40-2?
Thanks DJ great video bro!
Very informative DJ, thanks 👋😎🛤🚂
Glad you enjoyed it
nice explaination, you've caught my interest.i live 500 ft away from a NS main line.i can hear differences in engines as they pass.the southbound coal trains coming out of pa.will viberate the house windows.& DPU's at mid & tail.judging by the vibrations & sound the DPU's are pushing harder than the leading engines are pulling.& some even scream like a banshee that is louder than the diesel.i assumed an extremely high output generator under intense electrical load? thanks.
You are very wise! Yes, the auto pilot feature sometimes has the dpu shoving while lead is in dynamic braking! I hate this, makes me feel like we gonna pop a car off on a curve!
Looking great, DJ. Another great video, sir.
Thank you kindly
Fantastic video
Is there a calibration process before consisting engines or is there an automated program to get the velocities and acceleration within tolerance
Great question. Its automatic. But what I never mentioned is that if engines are radically different, we can feel one pushing or pulling the other sometimes.
@@djstrains interesting…thanks for responding!
Another banger DJ! 🎉 I wonder if your familiar with any of the railroad simulators such as Train Sim World? It would be nice to see a hands on approach to how you might operate a locomotive. Can’t wait for the six axle video. Thanks for all your hard work!
Honestly, I get asked often, but have no interest in simulators, sorry.
@@djstrains what? You don't want to pretend to be back at work - and not getting paid!? grin ...
Looks like CSX currently has about 35 MP15s.
in storage, lol.
great info DJ. thanks
These “SpongeBob” units do a boatload of work.
And 4 axles are preferred in many industrial branch lines.
Not that I would be a candidate to become an engineer but it has always fascinated me thinking about it. I am 51 and just became type 1 diabetic (or type 1.5 for anyone who knows) only 4 years ago. Do railroads have restrictions with hiring regarding type 1 diabetics?
no, we have a few already.
If you have air start locomotives which lost their air, if another unit is around you can just couple the MR hose from the live one.
Yes. But there was none in the yard that day and no "ground air" lines in Neville island yard either, sigh.
There’d be less chance of another unit, jumper cables, or a welder being available if a junkGE had dead batteries.
Thank-you!
Mike.
Not sure why TH-cam keeps unsubscribing me from your channel. Anyway thanks for the info, never felt right adding my GP to the front of a consist any of my long distance trains. I knew there was a reason lol
Man, TH-cam acts up all the time. I miss comments and sometimes up to a year before I catch it. Go watch the other 399 videos, lol!!
As always I learn a lot, thanks😀
Thanks buddy!
Nice Video
Thank you I enjoyed this viedo very much looking forward to your next
Glad you enjoyed it
You know what? I think i understand the mother slug concept. The slug provides even more traction without needing another diesel engine. You're getting twice as many traction motors with just one diesel engine
Great Video DJ.
Appreciate it
What are your thoughts regarding the Genset locomotives? My apologies if you have already mentioned them.
garbage. Even mechanical department hated them, lol.
@@djstrains Glad I sold my HO scale Genset power. LOL
Great content DJ. 👍😊
HUMBLED AND GRATEFUL!!! THANK YOU SINCERELY!!!
Conrail used GP unit's everywhere didn't matter in the 70's & 80's 9:15 Best way to Explain it is the mother & Slug Unit and why Concrete slabs are mostly found under the hoods of slugs is because the missing necessary weight of the primary Engine that has been removed, a Single Locomotive has an enough Voltage Power and Traction effort to pull more than 80 cars by themselves but needs more weight and it's power spread out as it can't because they will honestly slip when trying to do so but if it has another unit then it's stretching out the Locomotives Mass Volume of Traction effort by adding another locomotive or Slug ensures maximum power and torque of the Mother or and of Mainline Train Unit's when pushing or Pulling, mostly used in Yards on Humps as this is the Reason why this is possible with the help of a different gears on the Traction Motors of the Slug makes things come alive plus all Mother Units mated to Slugs top speed is restricted to 15mph when using them as the torque is too great for a top speed to handle. A flip of a switch in the mother unit the engineer can shut the power to the slug's traction motors off making the mother unit smooth riding and move faster when not coupled to said freight cars as this is what was done when I worked for Conrail may have changed now a days but not by much.
DJ, great video. Great explanation of rimpull (tractive effort) I will have to plagiarize when I teach NUBE Civil Engineers. Also, I think CSX has 1 or 2 of the MP 15s in Baldwin, Florida. At least something that looks a whole lot like the pic. Just a noisy diesel that they use to cut and build trains, fully remote. The conductor called it a "Butt Head". Again, great post, truly enjoy the videos and reading the comments. Looking forward to part 2.
I know there's one, the crews treat it like the short straw when it comes to power. I remember I was getting off a transfer job up there and having to wait for a track to be shoved back in before I crossed the yard from my motor. I see a cut creeping by consisting well cars, loaded ballast cars, then a lone MP15 absolutely screaming as it tried to move the train. I was riding with some old head engineer who just grunted and said "And they wonder why their s**t breaks" under his breath
@@intermodalman123 yep, that's about how the operations were going when I was able to observe while the i-10 bridge was being placed over the yard.