Do we know if there is point to point locking between points 105 and 106?
Things we know:
A GWR train (1F27 16:58 Bristol Parkway to Portsmouth Harbour) had left Salisbury at about 18:37 on the Up Main just before the incident. Going through the tunnel and crossing over the junction onto the Up Dean, but it stopped before it got to Dean.
GWR train (1F30 17:08 Portsmouth Harbour to Bristol Temple Meads) passed Dean (on the Down Dean line) at about 13:35, and approached the junction (Tunnel Junction), but for some reason stopped over the junction on the Down Main, with the rear part still on the junction, but with the front part in the tunnel. The front part does not look to be derailed in the photos.
We do not know why this train stopped, but drivers don’t stop their trains in a such a location without there being a good reason.
SWT train (1L53 1720 London Waterloo to Honiton) was in the area of Andover at 18:29 on the Down Main, it continued on towards Tunnel Junction and hit GWR train 1F30 at the junction where the Down Main and Down Dean converge. The collision resulted in it derailing and some of the units ending up at an angle. The leading cab suffering extensive damage.
The public live train websites (which obtain their feed via a Network Rail system that in turn gets some of its information from the various Train Describer systems) show the ‘head code’ (TD ‘number’) for 1L53 still in the ‘berth’ for signal SY31.
Questions (I not looking for answers, just things to think about, the kinds of questions that the investigators will be asking, so please don’t speculate here):
What was the reason that caused the driver of GWR train 1F30 to stop their train where they did? Did it actually hit something? Was there a problem with the points fittings (point number 106) ? Or was there a problem with the train? If this train did hit something or if there was a problem with 106 points, did this train derail?
Why did the TD not step the ‘head code’ forward for 1L53 when the train has clearly passed signal SY31?
If there was no problem with GWR train 1F30 operating the track circuits (where it is in the photos I would expect it to be on at least two track circuits) the interlocking should have held signal SY31 at red. So was there a problem with the track circuits?
In the photos, points 105 look to be lying reverse, as they would have been needed for the move of 1F27 over the junction. This is the opposite way to that required for 1L53 if there is point to point locking between points 105 and 106. We don’t know which way points 106 are because we can’t see them and they may be under the GWR train. If there is point to point locking, then if points 105 are not set correctly, signal SY31 should not clear. Was there a problem here?
Did the signaller route signal SY31? If the answer is no, then signal SY31 should not clear to a proceed aspect. Did signal SY31 stay red? Was it lit? What was the sighting like? Could approaching train drives see it clearly and at the required minimum distance?
If SY31 does not show an proceed aspect or if the signal is not illuminated , then the AWS should result in the AWS horn sounding in the leading cab of train 1L53. Was the track and lineside equipment for the AWS working? Was the train AWS equipment working?
SY31 should be fitted with TPWS equipment. The TPWS transmitter loops should be energised at all times unless the signal is showing a proceed aspect. Was the track and lineside equipment for the TPWS working? Was the train TPWS equipment working?
The signal, SY31 requires electricity to work, as does the TPWS. Was there a loss of power to this equipment, causing SY31 to go ‘black’ and disappear into the darkness? The signal identification plate/sign should be made of the reflective type so that it can be seen more easily in poor light conditions. Was it? Was it clean?
If there was a loss of power due to a fault with the signalling system, what caused this?
If there were no faults with the signalling system, was there a problem with the braking system on train 1L53? Or was there rail head contamination that reduced the effectiveness of the braking system?
I’m sure there are many other questions. As I said earlier, please don’t speculate. The facts will come out in the report once the investigation is complete.