Heat related speed restriction and CWR management

[danasgoodstuff]

Rail kinks like in Montana, is my guess.

 

[Devil's Advocate]

I have a friend aboard the Crescent tonight. They've been told the rain is terminating in Atlanta and they will be bussed to New Orleans. The reason given is that it's due to a heat advisory in the south. What would the issue be? It doesn't make sense to me that Amtrak can't run a train in the summer heat in the south.

Railroad track cannot be installed in a manner that is suitable for all possible temperatures. As temperatures increase the track can exceed the target temperature range when it was laid and may suffer a heat kink.

 

[railiner]

So...with all that...would jointed rail be better? At least in handling temperature extremes?

 

[jis]

I have seen these long structure which appear to be expansion devices used on Indian Railways. I wonder what are the factors that go into determining where to place them on a stretch of track on ground, i.e. not on bridge structures and such.

 

[xyzzy]

Many (most?) Indian Railways lines have a maximum axle loading that is considerably less than in the U.S.

 

[jis]

Many (most?) Indian Railways lines have a maximum axle loading that is considerably less than in the U.S.

What is the relevance of that to rail expansion? Do they expand and contract differently depending on axle load?

Axle load has effect on rail fatigue and could accelerate structural failure of rail. The other thing that higher axle load does is it requires more maintenance to maintain track quality for higher speed operations. This might be one of the factors why ride quality on passenger trains is uniformly worse in the US specially at higher speeds than in most other countries. Of course the fact that a few freight railroads skimp on the depth of ballast bed to save money does not help and also increases the chances of development of rail kink.

US Axle load is 32.5 - 36 Tons (29.5-32.7 Tonnes). Europe is generally 20-23 Tonnes. India is 22-25 Tonnes.

 

[tgstubbs1]

I have seen these long structure which appear to be expansion devices used on Indian Railways. I wonder what are the factors that go into determining where to place them on a stretch of track on ground, i.e. not on bridge structures and such.

How much distance between these devices? They don't look expensive.

 

[jis]

How much distance between these devices? They don't look expensive.

I found an Indian Railways tutorial on SEJ (Switch Expansion Joint). Unfortunately it is in Hindi and all its visuals are also in Hindi. But it is a veritable mine of information.

Some of the important things I learned is that all CWR segment have to be terminated at each end with SEJ. The maximum expansion gap is between 6cm and 8cm depending on the model (there are four models with variants to transition from 52kg/m and 60kg/m rails. Some models can be used on upto 2 deg curve, and others on upto 4 deg curve. One interesting fact is that they do inspection of the SEJs at least once a month on an average and if necessary destress the segment, noting the temperature at which it was destressed. I have no idea what the corresponding practice in the US is.

In case someone is fluent in Hindi and can read Devnagari script, here is the video. Not recommended for those who are not fluent in Hindi, but some of the diagrams may still be useful. There are photos of the various types of SEJ used too.



But the piece de resistance is the LWR Book of Indian Railways that I just found. It has everything that one might want to learn about LWR practices on IR and then some:

Long Welded Rails, Indian Railways Institute of Civil Engineering, Pune 411 001 (large PDF)

 

[Bob Dylan]

Crescent canceled past Atlanta due to heat (?) I have a friend aboard the Crescent tonight. They've been told the rain is terminating in Atlanta and they will be bussed to New Orleans. The reason given is that it's due to a heat advisory in the south. What would the issue be? It doesn't make sense to me that Amtrak can't run a train in the summer heat in the south.

The South and SW are experiencing unrelenting Record Heat ( 100-115) and the Rails are being distorted, which will cause Derailments and Accidents that none of us want!

Better to ride a Bus ATL-NOL than to be stranded in ATL with No Alternate Transportation!

 

[Metaterra]

True. It has not been a great trip for him. I have talked about how great travel by Amtrak is. So his first real overnight trip and he is put on a bus. He said the car was freezing last night (ironic) and he couldn't sleep, and the crew took all the tables in the dining car so passengers were restricted to their rooms and roomettes. Sounds awful but consistent with what I've heard here about the Crescent. I've ridden the Crescent three times but won't again when I go around the country next year. I'll fly to NOL and take the Sunset Limited from there.