5239 'Goliath'. Proving to everyone the name isn't just a load of hot air. Lovely video, showing quite clearly the inadequacies of running a fully loaded main line passenger locomotive on a steep undulating branch line. And it certainly won't be the last time this mistake is made.
This might seem like a small branch but it was a main line. The Torbay Express and I think the Devonian and certainly the Manchester-Kingswear used to terminate at Kingswear. There are numerous photos of Kings at Kingswear Station and near Churston, never mind lesser GWR express passenger locos. The difference between this train and those I have mentioned might, however, be in the loading. 11 coaches is a lot on Goodrington bank for any big engine and I suspect that the old trains may have had less when they were single headed.
I can't resist - surely you can see that both drivers would SHUT their regulators on slipping and the fact that the tank stops slipping straight away demonstrates that it has far superior ADHESION and this is the MAJOR factor in both locos performance!
td2901, A Castle is a 4-6-0. It has far superior adhesion qualities to a Pacific 4-6-2. A Bullied light Pacific, like Tangmere, was not intended for low speed slogging on heavy gradients, they are better suited to faster trains on more even terrain. There was a good reason for the GWR to favour 4-6-0's on the hilly terrain of the western region! Hope that helps.
Poor Tangmere. But, at the end of the day pacific's like her weren't built for severe hill climbing, they were built for speed and power.Whereas, that GWR tank was built to haul massive loads with its small wheels, perfect for the Welsh valley's. The power of the 2-8-0 best is dramatically shown in this video. Thanks for posting.
I love this video and have revisited it on many occasions. It just shows how poorly suited the pacific engines are to this kind of steep and twisting routes. Whereas our Hero here 'Goliath' (a fantastic name by the way) Is completely at home. This work is what she was designed to do, hauling heavy coal trains in the welsh valleys. 2-8-0 wheel arrangement with all of the water bearing down on the driving wheels! Plus the GWR bark, it doesn't get better than that!
Public footpath at the bottom of Waterside Holiday Park, The path runs from Paignton alongside the train line. I've only been as far as Broadsands Viaduct, so i can't say if the path continues on further.
Haha yes I saw that particulate train leaving Kingswere later in the day. I was annoyed about the class 25 being on the back as I thought an A4 would dance up that hill. Then I found out later it didn't manage. Oh FYI there's only one manor based here. The other engine around at that time would of been kinlet Hall that was on loan for a few months to cover in the summer
Thats a good point, I hadn't thought of that. I think it would be a good idea if one of the services this year was hauled by one of the 3 mainline operational a4s
@herbgarratt. If you compare A Stanier 8F 2-8-0 and a Stanier 5MT 4-6-0 both have Walshearts valve gear, both have the same boiler pressure, 2 cylinders, same bore and stroke - yet the 8F has 27% greater tractive effort due to its eight 4 foot 8 1/2 inch drivers against the six 5 foot 6 inch ones! And that is ALL this video shows - the advantages of 8 small driving wheels vs 6 large ones!
Surely something broke on the last big wheel slip. You can see then trying to restart. plenty of steam chest pressure but no valve travel. Just a weak gasp coming out the exhaust.
Yeah, i'm surpirised they've never thought of that. But when they get Tornado running, the A1s were powerful engines, with something like 37,000 pounds of tractive effort, they might be able to do it. Plus when Blue Peter is overhauled, get it do do it, the A2s has about 40,000 pounds of tractive effort
It just goes to show that the GWR locomotives must be the best. These Southern trains can't manage hills (just look at Exeter bank). The LNER A4's struggled on the same bit yet a small little ex Welsh coal tank can haul the entire train no problem.
No, not necessarily. Pacific's are approaching them at slow speeds and with an overloaded train so it is bound to struggle. Most Pacifics struggled on this line as they were not designed for running on this type of terrain.
@@Frserthegreenengine That's a fair point they were designed for running on fairly flat track at high speed. GWR's King's and Castle were designed to be able to do both.
@herbgarratt . The answer to both your questions is "it doesn't matter". The point you have yet to concede is that the tractive effort of the small drivered 8-coupled tank is much greater than that of the pacific - thus it's ease in lifting the train even if it had Walsheart's valve gear!!!!!
It's tractive effort is greater but not by very much. The tank has a TE of 33170 lb whereas the Spam's is 31050 lb. The real point is that the tank has an adhesion weight of about 72 tons whereas the Spam has only about 55 tons. Valve events are quite irrelevant; both locos are obviously in full gear and it make precious little difference whether the cut-off is 70, 80 or 90%
Thanks CGT. The real irony here, is that our herb hasn't thought throught his argument. He is discussing a peculiarity of valve event that only occurs at, or very close to top dead centre - when virtually no torque is being transmitted! Lead is probably very important for high speed engines working at speed on short cut offs, in order to get the steam into the cylinder more quickly for expansive working. But it would have no effect on a slow or stationary engine keeping her feet. IMO
Brilliant ! This could have been scripted from a "Thomas the Tank engine" episode with the little chap on a rescue mission..... Great viewing - thankyou !
Very right, thats exactly why... but of course the 2-8-0T is mean for freight and not fast passenger so thats why it would never haul the train on it's own. I understand these engines are so powerful they woul be happy pulling near 16M. 1's along a preserved line... Bring it on!!
HEY, why don't you all stop arguing, regardless of the differences between these loco's lets just appreciate the fact that dedicated people like myself and all you guys no doubt can donate money to keep these beauties running today nearly 40 years after they were taken out of service. I think you all need an early night...!
It's not necessarily all about tractive effort,though; remember Blue Peter at Durham? That's why the tank had so little trouble; eight small driving wheels v. six large ones.
"I cannot believe how poorly that 4-6-2 performed, how any touring company would want to use it on one of their services baffles me" The point is that it was overloaded if you take into account's it adhesion and tractive effort combined with the grade of the line and the load. How else do you think that a Bulleid and Standard five slipped to a stand at Exeter with a similar load?
O dear we are touchy aren't we! Whatever the lead characteristics of the two gears the basic problem for Tangmere remains an adhesive one, not a technical one.
Herb,listen to what others are saying - valve gear has NOTHING to do with it otherwise an 0-6-0 pannier tank would lift it and a 9F wouldn't! Watch how long the wheels spin after shutoff on Tangmere compared with the tank loco. It's ADHESION! Also compare the strength of the exhausts. Tangmere almost steams to a standstill - then can't lift it's train with sanders on. Too short a cutoff at maximum (or perhaps low on steam). The tank can use almost full throttle! Churchward wasn't a god.
The wheels on the Spam spun longer probably because the driver was slow in shutting the regulator which could well be because it's a more awkward to move, being the pull-out type. Tangmere steams to a standstill because the driver is deliberately soft-pedalling, using just enough regulator to keep the train moving. As soon as he gave it a bit more the engine slipped. The exhaust sound was a dead giveaway.
You're wasting your time on herbgarratt - he is obviously a guy who thinks that an 0-6-0 pannier tank could outpull a 9F 2-10-0 simply because of the type of valve gear and ignoring all the other factors that caused this train to stall!
@bineees78xx - dont quote me on this but havent the majority of the stations been engineered so the its flat for the length of the platform. Hense an easier get away? Also the straighter the track the better for traction? Feel free to correct me if Im wrong, im only guessing.
Straighter track won't improve traction but sharply curved track certainly increases the rolling resistance of the carriages meaning a stronger pull is needed.
Matt Veale. As a person who has been involved in rail preservation before a "dedicated" person like yourself was even born (and not just donating but restoring and operating) I think I can comment when I read idiotic comments on trains by "experts".
Whats all that crap about valve gear lead? It's all about a tractive effort of 27,700lbs from six large driving wheels compared with 33,270lbs from eight small driving wheels. Which do you think is going to pull better from a standing start?
Herb, I understand your point as you described it, but it doesn't support your case. First, we would have to assume that a minor resistance @ or near TDC from one cylinder, would induce an increase in effort from another, that a 400 ton train, gradient, & slow speed would not. Then we would have to assume, that despite Duke of Gloucester perhaps having more lead than any other British express engine, that she could never have kept her feet to break the record books on the Devon banks.
herbgarratt, since you are comparing a 3 cylinder locomotive to a 2 cylinder locomotive, then it should be obvious to you that the 3 cylinder engine would apply its torque in a far more even spread than the 2 cylinder one. The tank 2-8-0 barely slipped simply because even with its superior tractive effort, it also has superior adhesion with 8 coupled drivers opposed to 6!
"The one thing you haven't mentioned which is what the cut off is in full gear on the 2 locos.i.e. on mainline passenger locos the valve cut off in full gear can be as little as 75% of the piston stroke. I dont know what the figure is for the tank but you can bet its not 75%, more likely 80, 85 or 90%." I'm not aware of anything that doesn't go between 75% and 15% cut-off other than the Duke of Gloucester which can manage 8-83% IIRC....
Herb, you're very knowledgable on valve gear, & your point may be a valid one if comparing like for like. Eg, same cylinder dimensions & number, boiler pressure, wheel size & configuration, bar the valve events. But this is not like for like. No valvegear invented will make the torque peaks of a 2 cylinder as smooth as a 3 or 4. Also 3 cylinders will have smaller bores & therefore smaller peak torques compared to a 2. The 2-8-0 laid plenty of sand down as he approached the stricken train too.
It got more than "stuck"...... There's a video on here (somewhere) of Blue Peter destroying herself at Durham. Fortunately, that did not happen in this case.
How come the exhaust on the Pacific is so weak before it comes to a stand and why does it's driver give hardly any assistance to the tank engine when re-starting? Was he short on steam? The tank loco does 90% of the work!
(CGT867) I think the driver of the Spam was deliberately and very sensibly pussy-footing in order to avoid a slip but it slipped anyway, as these engines do if you open the regulator. The use of the 2-8-0 tank illustrates a persistent design fault in British express locos, the reluctance to use an eight-coupled design such as a 2-8-2 which would eliminate a lot of slipping. During the days of steam the idea seemed almost taboo - God knows why.
Must've been the same driver that attempted to do and stall at the same spot that drove Bitten to a stand still and then let their manor do all the lifting. Not good publicity is it for visiting locomotives is it?
Considering, that 11 bogies is unlikely to be the correct load for that route, and the poor locomotive has had its boiler pressure reduced from 280 psi to 250 psi, the far less experienced crew than those of pre-1977…. That was a wonderful job all round, and deserves 12 out of 10 for the hardware and human skills. That tank engine’s pretty cool too…
You obviously don't know that one advantage of a 3-cylinder engine is a more even torque spread which negates your theory. And just what is "negative" lead anyway? Can't find it in any valve gear books!
Can't resist. 95% Cut off, expansive properties of steam, lead and lap, valve gear, I think you may be missing the point. Tractive effort is a good place to start but the equation (see wikipedia)doesn't take full account of adhesion. Churward knew this. Only 4-6-0's (benefit of belpair fierbox) weight, equally distributed over the driving axles with the leading bogie doing what it should, guiding the loco into curves not supporting the loco. Heavier driver axle loadings = better adhesion.
Sorry to disappoint you herbgarratt but as a former engineman I know precisely what lap and lead are. But the gear is and always was referred to as 'Bulleid chain-driven gear.' Whoever saddled the engine with 11 coaches on a line of this severity was ignorant of the 'light pacifics' behaviour on the Somerset & Dorset when their slipping propensities meant they were restricted to a load of 270 tons or eight coaches over the Mendips between Bath and Evercreech, the same as LMS and Standard Fives.
The S&D had a max gradient over the Mendips of 1 in 50 for several miles. Hence the Bulleids and Black 5s being limited to 270 tons. This line has a max of 1 in 66 and the gradients are much shorter. But I agree that 11 coaches is too much for a pacific on this line and the S&D. The last Pines Express over the S&D was hauled single headed by a 9F, Evening Star with 450 tons behind it and with no trouble.
HerbGarratt - hopefully to silence you once and for all on this Tangmere stalled because it was obviously over the load.Once it lost momentum it was doomed.The one thing you haven't mentioned which is what the cut off is in full gear on the 2 locos.i.e. on mainline passenger locos the valve cut off in full gear can be as little as 75% of the piston stroke. I dont know what the figure is for the tank but you can bet its not 75%, more likely 80, 85 or 90%.
The maximum cutoff with the standard GWR version of Stephenson's Link motion is about 77%. The typical figure for the vast majority of locos is 75% except for Gresley 3-cylinder locos where it is 65%.
@herbgarratt We will have to agree to disagree on this. All I can add is that Australia and the USA have far heavier grades to start trains on than the "almighty" Great Western and they put Walshaerts on all their modern (and very sucessful) heavy freight locos so it can't have made much of a difference.
Tangmere isn’t the only engine to stall on this gradient... 2 years before this video... Union of South Africa (a Gresley A4 Pacific) stalled on the hill and had to be rescued by a Great Western Manor Class
Walschaerts is nothing to do with it either. In any case the GW used inside Walschaerts on all its 4-cyl locos. All Pacifics are slippy, mostly due to weight transfer, and Spams especially so because of low adhesion weight and oil from the bath getting on the wheel treads. The 3 cylinders should help, each thrust being smaller but no use in this case. Spams can slip on the flat light engine. A "disorderly locomotive" in many ways, despite much brilliance.
Herb, you started this by claiming this was a demonstration of the superiority of Stephensons valve gear. For the benefit of all the people who's arguments you have dismissed (including footplate men) please enlighten us - at which point does the video prove this? And why does the tank slip if it has no vexatious torque peaks? Why does its slip stop so quickly compared to the pacific?
How much does 11 carriages weigh? Apparently this railway likes to over load visiting locomotives. Not good publicity is it. They did the same thing with Bitten.
This is very bad management. This train should have a banker or double headed. I have reservations about allowing such badly managed services anywhere near the main line. This could have ended very badly if he'd lost his brakes and started sliding back. Once you loose brake and started sliding theres no way to hold the train back
I am so fed up with the older generation still arguing about who was the best designer, WHO GIVES A F***. I love steam engines but there all out of date, a steamloco being built now would have different technologie,probably we'd see a new variation of poppet valves and more. So just appreciate every steamloco, everybody has his favourites. But stop arguing about a discussion thats been going on for more than half a century now. We don't argue anymore about if the world is flat or round do we???
I appreciate your offer, Herb, but to be honest with you, the vagaries of valve gear operation are not of great interest to me. Not in the fine detail to which our discussion relates, put it that way. please don't take that in a personal way, as I've enjoyed our debate! I hope you have too.
About two carriages to much. Everytime she accelerate the driver go that extra tap on the regulater and slip. That's how I viewed this clip. Not blaming the driver in anyway but don't you think 11 carriages is a bit to much. But you have to admit she did sound awesome.🖒
Why do western driver's use the sanders where southern driver's don't. This locomotive could've dragged this train uphill but the crew had no patience. Why do these modern so-called steam driver's use the cylinder's cocks after the locomotive has stalled, flipping stupid. I suppose you get that with a driver used to driving small engine's on a branch line and then think's he knows how to drive a MAINLINER? I bet they don't overload their own locomotives.
That's a mighty exhaust on the tank loco!
It helps with all that water on top of small driving wheels. :) I love tank-engines. Lovely footage.
5239 'Goliath'. Proving to everyone the name isn't just a load of hot air.
Lovely video, showing quite clearly the inadequacies of running a fully loaded main line passenger locomotive on a steep undulating branch line.
And it certainly won't be the last time this mistake is made.
This might seem like a small branch but it was a main line. The Torbay Express and I think the Devonian and certainly the Manchester-Kingswear used to terminate at Kingswear. There are numerous photos of Kings at Kingswear Station and near Churston, never mind lesser GWR express passenger locos. The difference between this train and those I have mentioned might, however, be in the loading. 11 coaches is a lot on Goodrington bank for any big engine and I suspect that the old trains may have had less when they were single headed.
I can't resist - surely you can see that both drivers would SHUT their regulators on slipping and the fact that the tank stops slipping straight away demonstrates that it has far superior ADHESION and this is the MAJOR factor in both locos performance!
td2901, A Castle is a 4-6-0. It has far superior adhesion qualities to a Pacific 4-6-2. A Bullied light Pacific, like Tangmere, was not intended for low speed slogging on heavy gradients, they are better suited to faster trains on more even terrain. There was a good reason for the GWR to favour 4-6-0's on the hilly terrain of the western region! Hope that helps.
Poor Tangmere. But, at the end of the day pacific's like her weren't built for severe hill climbing, they were built for speed and power.Whereas, that GWR tank was built to haul massive loads with its small wheels, perfect for the Welsh valley's. The power of the 2-8-0 best is dramatically shown in this video. Thanks for posting.
Deserves a medal! Well done
I love this video and have revisited it on many occasions. It just shows how poorly suited the pacific engines are to this kind of steep and twisting routes. Whereas our Hero here 'Goliath' (a fantastic name by the way) Is completely at home. This work is what she was designed to do, hauling heavy coal trains in the welsh valleys. 2-8-0 wheel arrangement with all of the water bearing down on the driving wheels! Plus the GWR bark, it doesn't get better than that!
you carnt beat the gwr them tanks can pull a lot it made lite work of that lot good video never seen a loco stull like that
Brilliant location at Waterside. I am going there next year on my summer hols so I will be filming the normal PDSR trains and the Torbay
This movie proves how powerful those 2-8-0 tanks are.
Public footpath at the bottom of Waterside Holiday Park, The path runs from Paignton alongside the train line. I've only been as far as Broadsands Viaduct, so i can't say if the path continues on further.
Fantastic wish I had been there - well done
Haha yes I saw that particulate train leaving Kingswere later in the day. I was annoyed about the class 25 being on the back as I thought an A4 would dance up that hill. Then I found out later it didn't manage.
Oh FYI there's only one manor based here. The other engine around at that time would of been kinlet Hall that was on loan for a few months to cover in the summer
Thats a good point, I hadn't thought of that. I think it would be a good idea if one of the services this year was hauled by one of the 3 mainline operational a4s
@herbgarratt. If you compare A Stanier 8F 2-8-0 and a Stanier 5MT 4-6-0 both have Walshearts valve gear, both have the same boiler pressure, 2 cylinders, same bore and stroke - yet the 8F has 27% greater tractive effort due to its eight 4 foot 8 1/2 inch drivers against the six 5 foot 6 inch ones! And that is ALL this video shows - the advantages of 8 small driving wheels vs 6 large ones!
Pacifics did climb Devon banks over Dartmoor on the Southern line between Plymouth and Exeter via Tavistock and Okehampton with no apparent problems.
7:03 This is where tangmere got stuck and the tank engine was called in to help it
Talk about being in the right place at the right time... Brilliant..
Surely something broke on the last big wheel slip. You can see then trying to restart. plenty of steam chest pressure but no valve travel. Just a weak gasp coming out the exhaust.
Thats some serious power that 2-8-0 packs.
Yeah, i'm surpirised they've never thought of that. But when they get Tornado running, the
A1s were powerful engines, with something like 37,000 pounds of tractive effort, they might be able to do it. Plus when Blue Peter is overhauled, get it do do it, the A2s has about 40,000 pounds of tractive effort
Excellent video, just wish it was a couple of weeks earlier when I was there with you!!
It was the right place then eh?!!
It just goes to show that the GWR locomotives must be the best. These Southern trains can't manage hills (just look at Exeter bank). The LNER A4's struggled on the same bit yet a small little ex Welsh coal tank can haul the entire train no problem.
No, not necessarily. Pacific's are approaching them at slow speeds and with an overloaded train so it is bound to struggle. Most Pacifics struggled on this line as they were not designed for running on this type of terrain.
@@Frserthegreenengine That's a fair point they were designed for running on fairly flat track at high speed. GWR's King's and Castle were designed to be able to do both.
@herbgarratt . The answer to both your questions is "it doesn't matter". The point you have yet to concede is that the tractive effort of the small drivered 8-coupled tank is much greater than that of the pacific - thus it's ease in lifting the train even if it had Walsheart's valve gear!!!!!
It's tractive effort is greater but not by very much. The tank has a TE of 33170 lb whereas the Spam's is 31050 lb. The real point is that the tank has an adhesion weight of about 72 tons whereas the Spam has only about 55 tons. Valve events are quite irrelevant; both locos are obviously in full gear and it make precious little difference whether the cut-off is 70, 80 or 90%
Thanks CGT. The real irony here, is that our herb hasn't thought throught his argument. He is discussing a peculiarity of valve event that only occurs at, or very close to top dead centre - when virtually no torque is being transmitted!
Lead is probably very important for high speed engines working at speed on short cut offs, in order to get the steam into the cylinder more quickly for expansive working. But it would have no effect on a slow or stationary engine keeping her feet. IMO
Brilliant !
This could have been scripted from a "Thomas the Tank engine" episode with the little chap on a rescue mission..... Great viewing - thankyou !
so brilliant video this thank you veer much brilliant
Very right, thats exactly why... but of course the 2-8-0T is mean for freight and not fast passenger so thats why it would never haul the train on it's own.
I understand these engines are so powerful they woul be happy pulling near 16M. 1's along a preserved line... Bring it on!!
In circumstances such as this, GOOD valve timing and tractive weight, in concert, are essential.
I think we disagree less than we agree?
It's the maximum figure that is important, i.e. for how much of the stroke is live steam admitted at starting!
HEY, why don't you all stop arguing, regardless of the differences between these loco's lets just appreciate the fact that dedicated people like myself and all you guys no doubt can donate money to keep these beauties running today nearly 40 years after they were taken out of service.
I think you all need an early night...!
What's Walschaerts got to do with it ? Tangmere has Bulleid cain-driven gear. Only the rebuilds were equipped with Walschaerts.
It's not necessarily all about tractive effort,though; remember Blue Peter at Durham? That's why the tank had so little trouble; eight small driving wheels v. six large ones.
Now there was me thinking it was a photo opportunity stop with a bit more for the tourists (and video-ers)! Best beach in the country is Goodrington.
"I cannot believe how poorly that 4-6-2 performed, how any touring company would want to use it on one of their services baffles me"
The point is that it was overloaded if you take into account's it adhesion and tractive effort combined with the grade of the line and the load. How else do you think that a Bulleid and Standard five slipped to a stand at Exeter with a similar load?
also bear in mind that Tangmere is carring a full train with 300 people on board and 11 coaches on on a climb like that single handly.
O dear we are touchy aren't we! Whatever the lead characteristics of the two gears the basic problem for Tangmere remains an adhesive one, not a technical one.
Excellent stuff
Herb,listen to what others are saying - valve gear has NOTHING to do with it otherwise an 0-6-0 pannier tank would lift it and a 9F wouldn't! Watch how long the wheels spin after shutoff on Tangmere compared with the tank loco. It's ADHESION! Also compare the strength of the exhausts. Tangmere almost steams to a standstill - then can't lift it's train with sanders on. Too short a cutoff at maximum (or perhaps low on steam). The tank can use almost full throttle! Churchward wasn't a god.
The wheels on the Spam spun longer probably because the driver was slow in shutting the regulator which could well be because it's a more awkward to move, being the pull-out type. Tangmere steams to a standstill because the driver is deliberately soft-pedalling, using just enough regulator to keep the train moving. As soon as he gave it a bit more the engine slipped. The exhaust sound was a dead giveaway.
@ryskinner Yup. they just stuck a class 25 Diesel on the rear of the train to save this from happening again
they got rid of the 25 now as same thing happened with a A4 and the 25 couldnt push it, so got a class 37 instead
You're wasting your time on herbgarratt - he is obviously a guy who thinks that an 0-6-0 pannier tank could outpull a 9F 2-10-0 simply because of the type of valve gear and ignoring all the other factors that caused this train to stall!
@bineees78xx - dont quote me on this but havent the majority of the stations been engineered so the its flat for the length of the platform. Hense an easier get away?
Also the straighter the track the better for traction?
Feel free to correct me if Im wrong, im only guessing.
Straighter track won't improve traction but sharply curved track certainly increases the rolling resistance of the carriages meaning a stronger pull is needed.
No I don't remember Blue Peter at Durham. I never even knew it got stuck there
Matt Veale. As a person who has been involved in rail preservation before a "dedicated" person like yourself was even born (and not just donating but restoring and operating) I think I can comment when I read idiotic comments on trains by "experts".
Whats all that crap about valve gear lead? It's all about a tractive effort of 27,700lbs from six large driving wheels compared with 33,270lbs from eight small driving wheels. Which do you think is going to pull better from a standing start?
He was, can't you see the steam from them?
Herb, I understand your point as you described it, but it doesn't support your case. First, we would have to assume that a minor resistance @ or near TDC from one cylinder, would induce an increase in effort from another, that a 400 ton train, gradient, & slow speed would not. Then we would have to assume, that despite Duke of Gloucester perhaps having more lead than any other British express engine, that she could never have kept her feet to break the record books on the Devon banks.
herbgarratt, since you are comparing a 3 cylinder locomotive to a 2 cylinder locomotive, then it should be obvious to you that the 3 cylinder engine would apply its torque in a far more even spread than the 2 cylinder one. The tank 2-8-0 barely slipped simply because even with its superior tractive effort, it also has superior adhesion with 8 coupled drivers opposed to 6!
"The one thing you haven't mentioned which is what the cut off is in full gear on the 2 locos.i.e. on mainline passenger locos the valve cut off in full gear can be as little as 75% of the piston stroke. I dont know what the figure is for the tank but you can bet its not 75%, more likely 80, 85 or 90%."
I'm not aware of anything that doesn't go between 75% and 15% cut-off other than the Duke of Gloucester which can manage 8-83% IIRC....
yeah i know, i never mentioned that, i was on about Tangmere not the 2-8-0.
Herb, you're very knowledgable on valve gear, & your point may be a valid one if comparing like for like. Eg, same cylinder dimensions & number, boiler pressure, wheel size & configuration, bar the valve events. But this is not like for like. No valvegear invented will make the torque peaks of a 2 cylinder as smooth as a 3 or 4. Also 3 cylinders will have smaller bores & therefore smaller peak torques compared to a 2. The 2-8-0 laid plenty of sand down as he approached the stricken train too.
It got more than "stuck"......
There's a video on here (somewhere) of Blue Peter destroying herself at Durham.
Fortunately, that did not happen in this case.
How come the exhaust on the Pacific is so weak before it comes to a stand and why does it's driver give hardly any assistance to the tank engine when re-starting? Was he short on steam? The tank loco does 90% of the work!
(CGT867) I think the driver of the Spam was deliberately and very sensibly pussy-footing in order to avoid a slip but it slipped anyway, as these engines do if you open the regulator.
The use of the 2-8-0 tank illustrates a persistent design fault in British express locos, the reluctance to use an eight-coupled design such as a 2-8-2 which would eliminate a lot of slipping. During the days of steam the idea seemed almost taboo - God knows why.
Must've been the same driver that attempted to do and stall at the same spot that drove Bitten to a stand still and then let their manor do all the lifting. Not good publicity is it for visiting locomotives is it?
Wow. I guess the light Pacific's weren't designed for steep gradients.
I think it would behoove you to read the book about the 1948 interchange trials. Bullieds could climb! The climbing star though was a Royal Scott.
Considering, that 11 bogies is unlikely to be the correct load for that route, and the poor locomotive has had its boiler pressure reduced from 280 psi to 250 psi, the far less experienced crew than those of pre-1977…. That was a wonderful job all round, and deserves 12 out of 10 for the hardware and human skills. That tank engine’s pretty cool too…
A+ verry good video i like it from dave from leeds
There are two ways of doing things, Duck said....
Will this have done the loco any damage?
It's clear though that the 2-8-0 tank is providing all the low end grunt getting that train moving again :)
fantastic video. definate like and fave for me :)
we were the ones who had to repair it!!
just don't argue with GWR locos, plenty of power and don't take crap off nothing, love their bark.
You obviously don't know that one advantage of a 3-cylinder engine is a more even torque spread which negates your theory. And just what is "negative" lead anyway? Can't find it in any valve gear books!
Brilliant.
Strange how the same loco Made an easier job of leaving Plymouth than a King did.
Can't resist. 95% Cut off, expansive properties of steam, lead and lap, valve gear, I think you may be missing the point. Tractive effort is a good place to start but the equation (see wikipedia)doesn't take full account of adhesion. Churward knew this. Only 4-6-0's (benefit of belpair fierbox) weight, equally distributed over the driving axles with the leading bogie doing what it should, guiding the loco into curves not supporting the loco. Heavier driver axle loadings = better adhesion.
Amen to that!
where is this filmed from?
Dartmouth steam railway
Sorry to disappoint you herbgarratt but as a former engineman I know precisely what lap and lead are. But the gear is and always was referred to as 'Bulleid chain-driven gear.' Whoever saddled the engine with 11 coaches on a line of this severity was ignorant of the 'light pacifics' behaviour on the Somerset & Dorset when their slipping propensities meant they were restricted to a load of 270 tons or eight coaches over the Mendips between Bath and Evercreech, the same as LMS and Standard Fives.
The S&D had a max gradient over the Mendips of 1 in 50 for several miles. Hence the Bulleids and Black 5s being limited to 270 tons. This line has a max of 1 in 66 and the gradients are much shorter. But I agree that 11 coaches is too much for a pacific on this line and the S&D. The last Pines Express over the S&D was hauled single headed by a 9F, Evening Star with 450 tons behind it and with no trouble.
HerbGarratt - hopefully to silence you once and for all on this Tangmere stalled because it was obviously over the load.Once it lost momentum it was doomed.The one thing you haven't mentioned which is what the cut off is in full gear on the 2 locos.i.e. on mainline passenger locos the valve cut off in full gear can be as little as 75% of the piston stroke. I dont know what the figure is for the tank but you can bet its not 75%, more likely 80, 85 or 90%.
The maximum cutoff with the standard GWR version of Stephenson's Link motion is about 77%. The typical figure for the vast majority of locos is 75% except for Gresley 3-cylinder locos where it is 65%.
@herbgarratt We will have to agree to disagree on this. All I can add is that Australia and the USA have far heavier grades to start trains on than the "almighty" Great Western and they put Walshaerts on all their modern (and very sucessful) heavy freight locos so it can't have made much of a difference.
A bulleid being rescued by a GWR tank engine, R.I.P.
They are quite big tank engines. The biggest tank engine in the world is bigger than Tangmere, with 12 driving wheels.
Tangmere isn’t the only engine to stall on this gradient... 2 years before this video... Union of South Africa (a Gresley A4 Pacific) stalled on the hill and had to be rescued by a Great Western Manor Class
@@yoville73 and later on,the same case happened to Bittern. Can we all agree that this express has some type of curse tha makes the engine stall?
Walschaerts is nothing to do with it either. In any case the GW used inside Walschaerts on all its 4-cyl locos.
All Pacifics are slippy, mostly due to weight transfer, and Spams especially so because of low adhesion weight and oil from the bath getting on the wheel treads. The 3 cylinders should help, each thrust being smaller but no use in this case. Spams can slip on the flat light engine. A "disorderly locomotive" in many ways, despite much brilliance.
Herb, you started this by claiming this was a demonstration of the superiority of Stephensons valve gear. For the benefit of all the people who's arguments you have dismissed (including footplate men) please enlighten us - at which point does the video prove this? And why does the tank slip if it has no vexatious torque peaks? Why does its slip stop so quickly compared to the pacific?
According to your theory the class 9F's should have been built with Stephenson's link motion - get real!
Nice video! 5*
How much does 11 carriages weigh? Apparently this railway likes to over load visiting locomotives. Not good publicity is it. They did the same thing with Bitten.
type in Blue Peter Loses Grip in the search bar....
I cannot believe how poorly that 4-6-2 performed, how any touring company would want to use it on one of their services baffles me
This is very bad management. This train should have a banker or double headed. I have reservations about allowing such badly managed services anywhere near the main line. This could have ended very badly if he'd lost his brakes and started sliding back. Once you loose brake and started sliding theres no way to hold the train back
vtdimitrov,
Why would this be a true ecological disaster?
Its a couple of steam trains, not an oil spill!
I am so fed up with the older generation still arguing about who was the best designer, WHO GIVES A F***. I love steam engines but there all out of date, a steamloco being built now would have different technologie,probably we'd see a new variation of poppet valves and more. So just appreciate every steamloco, everybody has his favourites. But stop arguing about a discussion thats been going on for more than half a century now. We don't argue anymore about if the world is flat or round do we???
I appreciate your offer, Herb, but to be honest with you, the vagaries of valve gear operation are not of great interest to me. Not in the fine detail to which our discussion relates, put it that way. please don't take that in a personal way, as I've enjoyed our debate! I hope you have too.
thomas help train
About two carriages to much. Everytime she accelerate the driver go that extra tap on the regulater and slip. That's how I viewed this clip. Not blaming the driver in anyway but don't you think 11 carriages is a bit to much. But you have to admit she did sound awesome.🖒
Why do western driver's use the sanders where southern driver's don't. This locomotive could've dragged this train uphill but the crew had no patience. Why do these modern so-called steam driver's use the cylinder's cocks after the locomotive has stalled, flipping stupid. I suppose you get that with a driver used to driving small engine's on a branch line and then think's he knows how to drive a MAINLINER? I bet they don't overload their own locomotives.
Use the sanders for christs sake driver
type in torbay fire breather
In normal service this would never have been allowed. If you want to keep these engines alive stop this nonsense.
Yawn!!!