Heat-related temporary speed restrictions (TSRs)

Most of the Central is, of course, above ground, so expansion problems, for both conductor and running rails, will be akin to NR. Would there be different limits for tunnel and open sections?
TFL website currently stating
#Central Line: Severe delays due to heat related speed restrictions.

Apparently the Central line was reaching around 10mph in the open sections!

Amersham-Harrow
Chesham-Rickmansworth
Watford-Baker Street
Uxbridge-Baker Street.

I noticed Lambeth North has closed due to heat related issues. What could be the cause of this?

Thanks

Possible short working because of speed limits elsewhere on the line.

Or maybe the lifts con't reach the top level because the cables have expandsed

...and it's only going to be worse tomorrow.

The over arching travel advice is Do Not Travel.

EDIT oops just seen someone else made the same comment already.

The lift machine chamber was very hot, so the lifts failed.

That lesson has been learnt - albeit on a certain style of London bus that was built with an air-chill system which was not as effective as the bus designers had hoped but (because of the weight) not a proper air-conditioning system. These buses were later retrofitted with a few windows, albeit not at the front of the upper deck as per some historic bus designs.



A few days ago I was on an Overground train where the air-conditioning was either not working or set 'too high' in one of the carriages. Thankfully I was able to relocate to an adjacent carriage. I have no idea if the windows on these trains can be opened.

The worst offender in stock designs was undoubtedly the D78s when first introduced. They made changing at Mile End to the Central a positive experience.

That says more about poor design of the bus than anything else.


But ITYF re. air-con on buses in general, the size and weight and energy consumption of an air-con unit to effectively deal with a typical GB bus across the entire temperature range *and* deal with the door open close cycle is somewhat larger than practical. Hence non air-con buses are perceived to be better than air-con buses - there is the psychological effect of a hot air breeze from outside seems to do something than being sealed in a cooler box. Air-con tends to be percevied to be working better on coaches as they have a far lower door open/close cycle and the box remains closed for much longer periods.

And I have some experience of all this as part of my engineering background as a NBC engineering trainee was with Leyland Nationals (the first ones; not 'phase 2's) as they came up for their first heavy docks which included air-con unit attention and what we did and did not need to overhaul / remove / enchance / replace. OK one might argue that NBC non air con LNs of the late 1970s are a somewhat out of date example, but I suggest the principle still applies, it was large enough kit as it was.

James, my understanding:

In places the track has been expanding lengthwise beyond the expansion limits so that instead it buckles (there are short sections with kinks in) and at high speed this would potentially cause it to derail / crash.

At low speed it will feel somewhat like being on an aircraft that has hit severe air turbulence. Especially passengers who are standing / walking will be thrown about inside the train and very likely hurt / injured. Possibly severely

From my understanding from reading news reports, the speed restrictions are intended to reduce the forces imparted on the track (which iirc increase with the square of speed) which make them less likely to be damaged but also reduce the severity from any damage that is encountered.

The first image in spsmiler's tweet is from Donostia (Basque)/San Sebastián (Spanish) in north-east Spain, near the French border. The second image is from the same country (the train on the line with the kink is operated by CAF), possibly the same incident but I don't know.

Come now, it is 46 years since we had temperatures anything like the recent ones, and I don't expect there will be anything similar for another 40-50 years. Weather proofing trains becauce of a few days of warmer than average temperatures, seems to me, akin to mandating permanant snow ploughs because we occasionally get 100mm of snow. 

OTOH it can be argued that ubiquitous air conditioning adds to the Heat Island Effect and thus the incease in outdoor temperatures.