[smallspy]

I used to commute on VIA between Guelph & Toronto and we had to slow down for the same reason on super hot days. Kinda surprised (yet not), that we still haven't figured out how to fix this... 20 years later?

As Paul pointed out, this has been an issue for far, far longer than just 20 years. And the problem is that there is no real solution to it.

The actual problem is that our potential temperature range in this part of the world is just too great. Want to avoid slowdowns in the summer? The railways can increase the stressed temperature of the rails when they install them, but then instead you are going to have slowdowns in the winter when it gets really cold. And even more seriously, pull-aparts, when the rail suddenly fractures due to the cold.

Going back to jointed rail is not an option, either. For all of the headaches dealing with temperature swings, they pale in comparison with the amount of work necessary to deal with jointed rail - both in terms of the tracks themselves (checking bolts, checking gaps, falling joints, etc.), and the additional stress on the equipment itself.

The railways up here have decided that it is easier to deal with slowdowns on the hottest of days, so here we are.

Dan

 

[Northern Light]

As Paul pointed out, this has been an issue for far, far longer than just 20 years. And the problem is that there is no real solution to it.

The actual problem is that our potential temperature range in this part of the world is just too great. Want to avoid slowdowns in the summer? The railways can increase the stressed temperature of the rails when they install them, but then instead you are going to have slowdowns in the winter when it gets really cold. And even more seriously, pull-aparts, when the rail suddenly fractures due to the cold.

Going back to jointed rail is not an option, either. For all of the headaches dealing with temperature swings, they pale in comparison with the amount of work necessary to deal with jointed rail - both in terms of the tracks themselves (checking bolts, checking gaps, falling joints, etc.), and the additional stress on the equipment itself.

The railways up here have decided that it is easier to deal with slowdowns on the hottest of days, so here we are.

Dan

Dan, you got me doing some google-fu and I found this........:

Linked below:

https://railroads.dot.gov/sites/fra.dot.gov/files/fra_net/18248/RR_Rail%20Temperature%20Control%20System.pdf

I was curious on your take.

 

[DopeyFish]

Dan, you got me doing some google-fu and I found this........:

View attachment 573795
Linked below:

https://railroads.dot.gov/sites/fra.dot.gov/files/fra_net/18248/RR_Rail%20Temperature%20Control%20System.pdf

I was curious on your take.

why does it look like they're just applying a giant metal brick (assuming thermally conductive) to act as a heatsink

 

[reinventingthewheel]

Dan, you got me doing some google-fu and I found this........:

View attachment 573795
Linked below:

https://railroads.dot.gov/sites/fra.dot.gov/files/fra_net/18248/RR_Rail%20Temperature%20Control%20System.pdf

I was curious on your take.

I’m not Dan, but I am an engineer not entirley convinced by this paper’s methodology. The concept makes sense overall, just an overflow reservoir for heat and it’s only a brief report so I’m guessing there are many omitted details.

It’s a bit frustrating there’s no mention of testing with trains applying heat on track. The influx of heat from wheel friction would need to be rapidly transferred to the capacitive devices, which would initially be at steady state - the same temp as the hot rail. Whereas the rate of heat transfer between rail and atmosphere from ambient temperature changes would be much, much slower.

 

[crs1026]

why does it look like they're just applying a giant metal brick (assuming thermally conductive) to act as a heatsink

They are, and it's just a reversal of what railways have done for a century when rails need to be stretched - they place an oil-soaked medium (rope, basically) along a rail, and set it on fire.... the heat makes the rail expand.

The issue I would see is - now the rail is concealed, which might interfere with inspection and testing. And maintenance. I wonder how the "heat sink" would fare during tamping, ballasting, etc. And how would the heat sink fare when moisture gets in between, freezes, and now the contact with the rail is compromised. And what is a heat sink in summer becomes a cold sink in winter, possibly preventing rails from warming up as quickly. Also, can it handle vibration?

The nice thing about railway track is that, while there is a huge body of science and engineering knowledge in the design, it's dirt simple. My gut says keep it that way. But maybe there are potential applications.

Really, just slowing the trains is also a very simple solution - a bit inconvenient perhaps, and tricky to handle in a PR sense, but it works.

- Paul

 

[T3G]

Really, just slowing the trains is also a very simple solution - a bit inconvenient perhaps, and tricky to handle in a PR sense, but it works.

We in Toronto are not at all strangers to very slow rail traffic even on the coldest of days!

 

[allengeorge]

It applies to all railway tracks, especially welded rail - at higher temperature metal expands, and if that expansion happens along a very long piece of rail, the accumulated stress can create a kink in the rail. The track is designed and built to minimise this, but when the temperature reaches the 30's in bright sun, the risk is greater and it makes sense to play it safe. Lower speeds mean the stresses imposed by the train on the rail (which add to the thermal stresses) are less.
There were plenty of track patrols out there yesterday and this will no doubt continue as long as the weather holds.

Is there any way to mitigate this, given that such temperature extremes are unfortunately going to be a common occurrence going forward?

EDIT: oh. Sounds like “no”.

 

[Northern Light]

They are, and it's just a reversal of what railways have done for a century when rails need to be stretched - they place an oil-soaked medium (rope, basically) along a rail, and set it on fire.... the heat makes the rail expand.

The issue I would see is - now the rail is concealed, which might interfere with inspection and testing. And maintenance. I wonder how the "heat sink" would fare during tamping, ballasting, etc. And how would the heat sink fare when moisture gets in between, freezes, and now the contact with the rail is compromised. And what is a heat sink in summer becomes a cold sink in winter, possibly preventing rails from warming up as quickly. Also, can it handle vibration?

The nice thing about railway track is that, while there is a huge body of science and engineering knowledge in the design, it's dirt simple. My gut says keep it that way. But maybe there are potential applications.

Really, just slowing the trains is also a very simple solution - a bit inconvenient perhaps, and tricky to handle in a PR sense, but it works.

- Paul

Is there any practicality to using water spray to lower rail temperature?

Obviously one isn't going to put irrigation sprinklers across the national rail network; but I know that some railways in the world have tested a tank car that mists forward at the front of a train to mitigate the increased temp from rail friction.

I can't find any papers on how successful that was or was not.

Sprinklers or misters could be practical on a very limited basis in urban areas.......if they produce sufficient value. I just don't know if they do (I rather assume they do not, but defer to those more expert in such things)

 

[crs1026]

Is there any practicality to using water spray to lower rail temperature?

Obviously one isn't going to put irrigation sprinklers across the national rail network; but I know that some railways in the world have tested a tank car that mists forward at the front of a train to mitigate the increased temp from rail friction.

I can't find any papers on how successful that was or was not.

Sprinklers or misters could be practical on a very limited basis in urban areas.......if they produce sufficient value. I just don't know if they do (I rather assume they do not, but defer to those more expert in such things)

I'm no expert in the technology, but on a high level I would doubt that the idea would be practical.....the train's passage magnifies the risk, but the risk of track failure is present even before the train passes.

If one wanted a little more technical explanation, this TSB accident report may be helpful

Rail transportation safety investigation report R21M0027 - Transportation Safety Board of Canada

Main-track train derailment, Canadian National Railway Company, Train B73041-15, Mile 18.9, Napadogan Subdivision, Pangburn Station, New Brunswick, 21 August 2021

www.tsb.gc.ca

- Paul

 

[smallspy]

Dan, you got me doing some google-fu and I found this........:

View attachment 573795
Linked below:

https://railroads.dot.gov/sites/fra.dot.gov/files/fra_net/18248/RR_Rail%20Temperature%20Control%20System.pdf

I was curious on your take.

I'm with Paul - it's an interesting idea (and already done in limited cases with third rail, but for entirely different reasons), but I don't think that it is a particularly practical one.

Is there any practicality to using water spray to lower rail temperature?

Obviously one isn't going to put irrigation sprinklers across the national rail network; but I know that some railways in the world have tested a tank car that mists forward at the front of a train to mitigate the increased temp from rail friction.

I can't find any papers on how successful that was or was not.

Sprinklers or misters could be practical on a very limited basis in urban areas.......if they produce sufficient value. I just don't know if they do (I rather assume they do not, but defer to those more expert in such things)

As far as I can figure to be effective at combating high rail temperatures, the spray would have to be installed on the wayside rather than on the equipment. And in which case, you run into many of the same issues as using the aluminum blocks as heat sinks ideas, plus the additional potential concerns of ongoing maintenance, long term effects of water on ballast (carrying fines and causing clogging), etc.

There are a number of countries that have taken to painting the rail in an effort to reduce or at least help mitigate the effects of high temperature. I need to read more to see if something like that is actually effective, and if so, just how much.

Dan

 

[Coolibop]

I'm with Paul - it's an interesting idea (and already done in limited cases with third rail, but for entirely different reasons), but I don't think that it is a particularly practical one.


As far as I can figure to be effective at combating high rail temperatures, the spray would have to be installed on the wayside rather than on the equipment. And in which case, you run into many of the same issues as using the aluminum blocks as heat sinks ideas, plus the additional potential concerns of ongoing maintenance, long term effects of water on ballast (carrying fines and causing clogging), etc.

There are a number of countries that have taken to painting the rail in an effort to reduce or at least help mitigate the effects of high temperature. I need to read more to see if something like that is actually effective, and if so, just how much.

Dan

We have had this conversation before..... For more see:

Question and not sure where it should go.

Has ML thought of painting the rail to deal with heat and buckling like Europe??

Rails in Europe have a white colour on them other than the top. This includes High Speed lines. Even subways lines not underground:

 

[drum118]

We have had this conversation before..... For more see:

Even though Europe paint their rails, they reduced the speed as well. There are many places where rail isn't painted, but speed is reduced to match the temperature/

 

[dowlingm]

There is a proposal in California to erect solar panels over canals, with a supposed win win of additional generation capacity while reducing water temperature and thus evaporation losses.

Have wondered in the past if something similar would work for rail lines at critical spots, but the clearance above rail would presumably require large structures to sufficiently shade the rail during significant heating hours while withstanding air pressure changes from passing trains.

 

[crs1026]

There is a proposal in California to erect solar panels over canals, with a supposed win win of additional generation capacity while reducing water temperature and thus evaporation losses.

Have wondered in the past if something similar would work for rail lines at critical spots, but the clearance above rail would presumably require large structures to sufficiently shade the rail during significant heating hours while withstanding air pressure changes from passing trains.

That may work in California, but be careful what you ask for.... as Dan explained, cooler in summer also means colder in winter. There are times of the year when the rails benefit from a warm sunny day. In particular, I would not be putting track switches in the shade as the drying/melting value is a good thing when the temperature falls below freezing..

- Paul

 

[dowlingm]

That may work in California, but be careful what you ask for.... as Dan explained, cooler in summer also means colder in winter. There are times of the year when the rails benefit from a warm sunny day. In particular, I would not be putting track switches in the shade as the drying/melting value is a good thing when the temperature falls below freezing..

- Paul

I get what you mean but it may be that they could be seasonally removed.

The other thing to consider is that solar angle is much lower in winter so depending on installation inclination, if left in place it may partially shelter from snow while the insolation is still possible underneath (the shadow falling on the side of the trackage). Probably something easier to finesse on a single track route though.

The other issue I have wondered about is whether shading the tracks would assist vegetation control on lightly operated trackage.