There Are 4 Rails on Railway Bridges, But Why?

Hello railway people, welcome to my new educational video about railways. Today, I will explain why we have 4 rails on bridges, but some other places as well.
This was something that bothered me few years back as well, especially as I was very interested in track design. Reason behind having 4 rails on bridges is very logical, to prevent train flipping over the bridge if derailment happens.
Note that not all bridges have them, depending on country, bridge position and similar. However, as a track designer I would always suggest to have them, as they can be efficient in reducing infrastructure damage or higher fatalities.
Let me know what you think about this in comment below. I would appreciate if you like, share or subscribe to my channel. This helps other people find out some interesting facts about railways too.
Railway Track Design Course: www.railgenics.com/rail-track...
My website: www.railgenics.com/
Music by bensound.com

[@rogerfroud300]

You could also argue that the additional rails stabilise the position of the sleepers, giving additional strength to the track and helping to reduce the chances of buckling and movement.

[@erniemathews5085]

I always wondered. Thanks.

[@goziegoziego232]

Thanks❤

[@stroberi1238]

Are there any recorded cases where guardrails actually helped?

[@thenetheriteminecart384]

They are called check rails, not guard rails, just to clarify things a little bit, and they are usually on bridges, tunnels and tight curves to keep a derailed train moving in the same direction instead of diverting off of a bridge or into a tunnel wall. Here is a short video that gives an explanation of why more than 2 rails: th-cam.com/users/shorts6kduAGfbx7U it tells you about duel gauge (usually 4 rails or gornplet track which is 4 rail duel gauge and about check rails which also are on points)

[@ThePaulv12]

@@thenetheriteminecart384 It's called gantlet or gauntlet track not gornplet track.
It can and is called guard rail.

[@thenetheriteminecart384]

@@ThePaulv12 Here in Australia, the UK and in many other European countries we call it check rails, and sorry for the typo but it is pronounced as gornplet track, although Australia is more in Asia but is its own continent if that makes any sense but Australia speaks kinda British but some things are American styled, it's a hybrid of the UK and America.

[@davidchapman1519]

Thought this was common knowledge

[@graemehamilton-gs7wp]

Koo chears

[@wade3217]

Now I know

[@hentichan]

just one hint, if you talk about something, explain ALSO how it works, not only why its there
Edit: please look at " ccrx 6700 That's Railroadin! ", he does a better explanation, where he also explain, how it should work to prevent cars from falling down.
if you do this on your Vids, than they will be a lot better

[@railgenics]

Thanks for hint, I will make it better next time :)

[@Inkling777]

I agree. I wanted to know how these guard rails work. What do they do to make a derailment less likely?

[@railgenics]

​@@Inkling777 They do nothing to make derailment less likely. That's not why they are placed on the track. They are there in case a derailment happens. Their function is to serve as another rail which will be hit by a train wheel when it derails. The idea is that the train wheel bounces off this rail and stays in between track rail and guard rail. That will prevent the train bouncing off the track during derailment, but also protect it against flipping over. Of course, this is not guarantee that it won't happen, as it depends on many factors such as speed, train type, track geometry etc. Main reason why they are placed on bridges and stations is that those are critical places in terms of infrastructure, interaction with other modes, number of people interacting at stations for example, etc. Hopefully this explains a bit more.

[@tetedepoulet8651]

Yes, the WHY would be nice