High Rail Temperatures from 23/7/19

How badly does rail around London get sun kinks? Normally I don't think of that as a problem below at least 40. (And, by extension, how much bolted rail is left in the system or is it 100% welded?)

Apropos of that, I found a spec about in the Central Florida Rail Corridor that has the desired rail neutral temperature at 40C and indicated a speed restriction if the actual is 23 over that. Don't know how that translates to UK practice.

corporate.sunrail.com/wp-content/uploads/2015/06/CFRC-CWR-Plan-Rev-3-11-27-13.pdf

Back in the great heatwave of '76, I was on a journey into London, and for parts of the journey the train was being very violently jolted sideways every few seconds. I was surprised that the driver continued at full speed (an assumption - it appeared to be full speed, and the train arrived on time).

zbang , There is still a large amount of rail miles in London that have yet to be turned over to continuous welded rail. Alot of the heat related speed restrictions on the 3rd rail network derived from the fact that many of the components were simply not built to operate under sustained high temperatures that have now become the norm in the summer.

Met Office going for 38C in London on Thursday. That will cause a few issues.

...wonders what the actual rail temperatures will be...

If not built for 40C ambient temps, what temps were expected on the not-underground lines? Surely in the last 30-40 years the permanent way forces would have taken hot weather into account on renewal projects (or not?). At least in the southern counties, even winter temps don't drop below -10C, so rail tensions shouldn't need to be slack enough to avoid cold-related pull-aparts.

OTOH, and there always is one, if jointed rail is just laid down at whatever temperature today happens to be, lines set in a 5C winter could have problems in a 35C summer. (A lot of the western US lines have this problem although they're mostly CWR.)

The Bigger the temp range the bigger the issues, though there are many places with much greater variances than here.

The problem is not just about running rails points also cause issues.

ExpectIng quite a few delays on the surface sections of the Underground too.

Following up here-
Have there been any actual incidences with the rails going out of line, points machines jamming, or signal problems (attributed to heat)?

(I'm not saying this doesn't happen or that caution isn't mandated. Just curious how the infrastructure has behaved.)

Two occurrences spring to mind, though neither are LU.

The first was in Cumbria and resulted in an RAIB report:

www.gov.uk/raib-reports/derailment-of-a-passenger-train-near-cummersdale-cumbria

The second in Australia was captured on camera, I don't know the outcome though:

Ive personally had good results in reducing the temperature in a loft with three south facing velux windows by putting up solar film on the glass each May and removing in September. Has reduced the temperature by at least 3 degrees versus without over the past two summers. I rip off for the other seasons as I use a film with the highest solar blocking, which reduces light also. Fine for summer but need the light outside summer so don't leave on permanently.
Tinted train and car windows are standard in places like Australia. Perhaps they should be considered for mid life refreshes. I was personally surprised the S stock didn't use tinted windows. The solar gain on even short sections in summer on the S stock is noticeable, such as West Brompton to Wimbledon.
London has much lower summer nighttime temperatures than most hot places, so I think storing trains with doors open is sensible, and worth trialling.

I know of some in 'sidings' that were affected on Thursday...

I often think that 'flange climb' risk would be lessend by having deeper flanges . When you look at images of wheel flanges, they appear to be rather small compared to the depth of rail etc: There is probably a good reason for the present dimensions --any answers?