Could a refrigeration system reduce points failures during hot weather?

[MotCO]

various mitigations have been tried over the years to reduce the failure rate of these points - including, at one stage, a sprinkler system. The only reliable mitigation to avoid the points failing is to take them, and two similar sets of points south of Harrow, out of service when the rail temperature gets too high.

Some points have electric heaters so that they do not freeze in winter - could you have some sort of refrigeration system which would cool the metal so that they do not over - expand? Maybe coupled with side protectors so that heat from the sun when not directly overhead hits the protectors and not the track.

By way of background, this thread ( https://www.railforums.co.uk/thread...nning-on-slow-line.247632/page-2#post-6199009 ) asked why fast Metropolitan trains were running on the slow line, and the answer was that a set of points was running hot due to direct sunlight in recent high temperatures. I was therefore wondering if there were other ways in which tracks could be kept cool, particularly at critical points, to avoid disruption.

 

[30907]

White paint is quite effective apparently, and its use is spreading northward through Europe

A complication AIUI is that the problem sections of track vary - age of paintwork, state of ballast, recent maintenance have been mentioned on other threads - whereas points freeze consistently.

That said, this particular issue I think relates to switch diamonds which are particularly prone to failure, so refrigerant is an interesting idea - I suspect it is rather costly to implement though. Protecting from direct sunlight might be rather difficult, as you would need one half of the shielding in the four-foot.

 

[MarkyT]

White paint is quite effective apparently, and its use is spreading northward through Europe

A complication AIUI is that the problem sections of track vary - age of paintwork, state of ballast, recent maintenance have been mentioned on other threads - whereas points freeze consistently.

That said, this particular issue I think relates to switch diamonds which are particularly prone to failure, so refrigerant is an interesting idea - I suspect it is rather costly to implement though. Protecting from direct sunlight might be rather difficult, as you would need one half of the shielding in the four-foot.

I think switch diamonds were some of the first UK track elements to get the white paint treatment, probably 20 years ago or more; they're terrible things to keep in adjustment through changing temperature conditions! The idea of some sort of more advanced temperature management system is rather compelling.

 

[Railsigns]

The attached photo shows sprinklers in operation at a switch diamond at Grangemouth Junction in 1992.

 

[30907]

The attached photo shows sprinklers in operation at a switch diamond at Grangemouth Junction in 1992.

View attachment 134282

That looks easier than refrigeration

 

[Elecman]

That looks easier than refrigeration

Expensive to run as water is becoming an expensive commodity to waste like that

 

[MarkyT]

The attached photo shows sprinklers in operation at a switch diamond at Grangemouth Junction in 1992.

View attachment 134282

Interesting!

That looks easier than refrigeration

A very rudimentary form!

Expensive to run as water is becoming an expensive commodity to waste like that

You'd probably not want it to run in very cold weather unless the water was able to be warmed like the sprinklers used for snow and ice control in Japan on roads and railways.

 

[TSG]

That it was too hot for switch diamonds in Grangemouth in 1992 says a lot. Never mind refrigeration, they are a bloody curse and should all be relayed with a maintainable layout

 

[Trainbike46]

You'd probably not want it to run in very cold weather unless the water was able to be warmed like the sprinklers used for snow and ice control in Japan on roads and railways.

you'd only ever want to run these sprinklers in hot weather, as that is when cooling would be necessary, right? maybe couple it to a thermostat attached to the tracks or something?

 

[MarkyT]

you'd only ever want to run these sprinklers in hot weather, as that is when cooling would be necessary, right? maybe couple it to a thermostat attached to the tracks or something?

Agreed of course, but in event of sensor failure cold water spray might result in ice formation. I was surprised by the Japanese sprinklers, according to the linked video only gently warmed by geothermal energy. Shades of ground source heat pump tech. I've also seen video of very rapid heavy duty deicing applied to running gear of a mini Shinkansen using hotter water at a special installation the train pulled into while in passenger service.

 

[Irascible]

Have there been any trials of some sort of passive cooling ( other than paint! ) - fins under the rail, some variant of heat pipe. or anything that'd move heat elsewhere ( although I guess that'd have to be electrically insulated ). Ballast is probably not a great material to dump heat into, unfortunately.