Engineering solutions to hot weather failures

[saltywalrus]

At present, there seems to be an acceptance that hot weather will inevitably lead to failures on the railway. When hot weather does occur, the response seems to be limited to mitigation measures (painting some track white, do not travel notices, key route strategies, etc.), rather than measures to prevent overheating in the first place.

I don't mean to criticise this approach - I'm sure NR and the TOCs have examined potential solutions but have deemed them impractical and/or uneconomical for one reason or another. But I'm curious as to what those solutions might be if resources weren't so limited.

Some ideas I had;

1. Tarpaulin canopies built over lines to shade them from direct sunlight. Would keep rails continuously shaded so they wouldn't be much hotter than ambient air temperature. Would obviously be an enormous capital cost to fit over the entire GB network, so would probably only be worth installing over major junctions where high rail temperatures are more likely to cause major disruption through points failures. Can imagine they might be a nightmare to maintain too - might need to be more of a net than a canopy to prevent water accumulation and prevent them from becoming sails in high winds.

2. Modified RHTTs than can spray low-pressure water onto the rails. Would potentially allow the entire network to be cooled without significant infrastructure investment, but might be a nightmare to fit RHTTs in around the regular timetable. I also haven't run the numbers, so it might only be able to cool short sections of rail before needing refilling.

3. Sprinkler systems to spray water onto the tracks. Similiar to 2, but switching high OpEx for high CapEx. Would probably only be feasible to fit to S&C, similiar to 1.

Any more ideas / criticisms / comments welcome.

 

[The Planner]

Spraying water on the track with these railhead temps would just evaporate and heat back up in seconds. Tarpaulins would just increase the temperature surely as it has nowhere to go.

 

[Zomboid]

Plant some nice fast growing, tall trees (leylandii...) on the southern side of all railways.

Wouldn't do a lot for north-south routes, admittedly.

 

[Bletchleyite]

I'm sure I recall reading that some countries that have both extremes of temperature e.g. Switzerland just restress rails twice a year accordingly. The UK doesn't do that at present in my understanding, we will probably have to start doing so if our climate, as it seems, is to become more varied than it was, with higher summer temperatures and potentially lower winter ones.

 

[HSTEd]

I think any water spraying arrangements would have to be fixed, you'd never be able to deliver enough water otherwise.

Putting the railway under a concrete hood would probably do ok as long as you arranged for good ventilation -but it would be very expensive. Could probably do something like that a Belgian high speed railway and put solar panels on the lines roof though

 

[Ploughman]

Spraying water on the track with these railhead temps would just evaporate and heat back up in seconds. Tarpaulins would just increase the temperature surely as it has nowhere to go.

Spraying water might not be a good idea considering the drainage problems in numerous locations.

Tarpaulins would act like a sail and also likely to put side loads on to whatever structures they are fastened to.
How often do you see a vehicle on the roads with a sheet flapping?

 

[saltywalrus]

Spraying water on the track with these railhead temps would just evaporate and heat back up in seconds. Tarpaulins would just increase the temperature surely as it has nowhere to go.

That's the idea - water evaporates and takes the heat from the rails with it. Might need an awful lot of water to cool them down though

Plant some nice fast growing, tall trees (leylandii...) on the southern side of all railways.

Wouldn't do a lot for north-south routes, admittedly.

Would be very nice, but wouldn't it cause adhesion issues in autumn?

I'm sure I recall reading that some countries that have both extremes of temperature e.g. Switzerland just restress rails twice a year accordingly. The UK doesn't do that at present in my understanding, we will probably have to start doing so if our climate, as it seems, is to become more varied than it was, with higher summer temperatures and potentially lower winter ones.

If re-stressing can be done twice a year, this seems like the simplest solution.

 

[HSTEd]

Would be very nice, but wouldn't it cause adhesion issues in autumn?

Maybe not if you plant evergreen plants.

 

[The Planner]

That's the idea - water evaporates and takes the heat from the rails with it. Might need an awful lot of water to cool them down though

Yes, but in this heat, that cooling will last a minuscule amount of time.

 

[swt_passenger]

One thing that is done in some important areas, (that the first post doesn’t list), is painting the web of the rail white in areas of complex S&C. (Points.). I think someone once gave figures about what it achieved - a drop of high single figures IIRC?

 

[saltywalrus]

One thing that is done in some important areas, (that the first post doesn’t list), is painting the web of the rail white in areas of complex S&C. (Points.). I think someone once gave figures about what it achieved - a drop of high single figures IIRC?

I think I mentioned it as one of the mitigations currently in place - it seems like an easy way to decrease rail temperatures, but it only reduces the temperature of the rails somewhat like you mentioned. Definitely better than nothing though.

 

[swt_passenger]

I think I mentioned it as one of the mitigations currently in place - it seems like an easy way to decrease rail temperatures, but it only reduces the temperature of the rails somewhat like you mentioned. Definitely better than nothing though.

Sorry, I missed that section when I first read it.

 

[alxndr]

3. Sprinkler systems to spray water onto the tracks. Similiar to 2, but switching high OpEx for high CapEx. Would probably only be feasible to fit to S&C, similiar to 1.

I did a fairly rudimentary experiment to test this with a bit of rail after we had ongoing issues with a particularly problematic bit of S&C. I can’t find the exact readings now but it didn’t make a big enough difference for us to continue with the idea of trying to rig up a system despite having mains water relatively near.

Another idea I mooted was using the switch heaters to keep the rails consistently hot at that location as it was the temperature swings causing the issue, but this has its own issues with drying out grease. As it happened the summer ended before I could persuade anyone to trial it.

 

[Bald Rick]

I'm sure I recall reading that some countries that have both extremes of temperature e.g. Switzerland just restress rails twice a year accordingly. The UK doesn't do that at present in my understanding, we will probably have to start doing so if our climate, as it seems, is to become more varied than it was, with higher summer temperatures and potentially lower winter ones.

I’m not sure if the Swiss restress twice a year, but I gather the Russians do.

However speed restrictions caused by the risk of track buckles are almost always only ever as a result of:

1) Recent work done to the track
2) incomplete records.

Clearly 2 is a process issue that needs sorting, and is much improved than it was 20 years ago.

1) means not tamping, or in any way disturbing the ballast for several weeks before hot weather. Given we get a maximum of 10 days notice of hot weather (and often less), the answer is therefore to not do any work that disturbs the ballast between the end of April and September. This is what some other countries do where they have high temperatures / temperature swings.