Not quite. According to @Phil H 's most helpful and timely post #828, Andrew Hall of RAIB stated that "the most likely cause ... was wheelslide, almost certainly a result of low adhesion between the wheels and the track. We are continuing to pursue this as a line of investigation amongst others." [my italics]
www.newcivilengineer.com
What do you mean by tpws speed limit? OSS loops?
Yes, there was a secondary low that developed and, as you say, generated a sting jet in a swathe from the south coast to Lincolnshire. There are reports of a short-lived spin-up tornado from this jet in Northants later in the day.
Possibly, yes. It is about energy disspitation. A car hitting a wall/tree at 70mph is very different to one barrel rolling a few times (at a basic level, obviously accounting for a lot of other variables)
Extreme/ adverse weather conditions ( a la Carmont?):
I’d imagine at that location the junction signal will have tpws and there will be OSS on approach to it. I doubt the signal that was showing the yellow would have anything as the line speed is only 50 mph (I don’t sign the route though so happy to be corrected).
A good point, and reason for not making the call (we don't know either way).
Entering the tunnel from the east there is a name board "Salisbury Tunnel". Entering it from the west (I.e. from the station) there is a name board "Fisherton Tunnel". I guess both names are valid ?
The signal does have TPWS overspeed sensors and they are set at 34.9mph
Carmont was caused by a slipped man made drainage channel
All the more reason for a site specific risk assessment. Anything that might destabilise an existing site, including maybe clearing out a blocked drain, needs to be adequately assessed by somebody suitably qualified.
Quite. I have just heard the police announcement on the radio that they have decided that wheel slide was almost certainly the cause. I think I read up-thread that the RHTT had not operated the day/night before? If so, this makes it even less appropriate for a 'knee-jerk'. However, even if an RHTT had passed only, say, an hour before, it's still easily possible for clouds of leaves to fall and be plastered to the rails by heavy rain, so the failure to operate one RHTT cannot necessarily be relied upon as the whole cause. The timing of the two trains seems especially unlucky - a few seconds either way would probably have avoided the impact.
www.realtimetrains.co.uk
including the running of RHTT trains, and management of the consequences of them not running as was alluded to upthread.
Of this I have no doubt whatsoever sadly.
We can at least be thankful that one of those wasn't on the front of the Waterloo train - the consequences for passengers on the other train (especially if it had been Mark 1 stock) would have been much more severe.
IIRC, the nameboard in the 'vee' of the junction reads "Salisbury Tunnel Junction", which is the correct name of the junction; whereas the nameboard at the Western end of the tunnel reads 'Fisherton Tunnel' - which is the correct name of the tunnel.
The severity of the Carmont derailment followed from the train having hit the bridge parapet at speed. I note from the post-reinstatement images that guard-rails are now fitted in the four-foot across the bridge and on the approaches to it where there were none previously.
Nope, it’s a spad.
It kicks in all the time on 158s at this time of year. It can be a bit alarming if you're not used to it, you get a lot of juddering, hissing and vibrating.
