edwin_m
Veteran Member
Unless I misheard, I thought the track cleaners at the start of the programme cleaned the human waste from platform 2, only to do it again to allow the track engineers repair the track after the derailment. I appreciate they were probably filmed weeks apart, but the continuity could have been better.
Where they were clearing was ballasted track so further down the platform than the bit where the derailment was. You saw at one stage how the track changes part way down the platform from ballasted to baseplates fixed directly to longitudinal timbers. Anyone know why it does so? The conventional sleepered track had canvas mats to catch the waste and they were filmed replacing these, but the track nearer the buffer stops didn't have these and would have needed pumping out somehow (as seen towards the end of the programme). So the two ends of the platform needed different processes and possibly different people.
Can anyone here shed light on concrete sleepers vs wooden sleepers, and what the decision process is for laying tracks on wood or concrete? I was surprised the Paddington sleepers were all wood (and even more surprised that they perished without anyone realising!) What would be the thought process behind making the entire track bed there out of wood? Cost?
As per above, where the derailment took place the track isn't carried on standard sleepers. Each rail sits on longitudinal timbers which are attached to a concrete base forming a trough with various cross-timbers spanning across to maintain the gauge (or not as the case may be). Even before the RAIB report I think we can safely say the cause of derailment was rotting of this timberwork.
This is obviously some sort of non-standard trackform which would require specialised castings if done in concrete, so probably easier to use timber instead. The track further out, under the canvas mats, appeared to be standard timber sleepers but I don't think there was any suggestion they had rotted away.