Dingwall derailment -- RAIB bulletin

[martin_wynne]

This bulletin just published today by RAIB includes some interesting diagrams of self-acting points (Hydro-Pneumatic Self Restoring points):

 

RAIB Bulletin

 

Martin.

[Glorious NSE]

That's not my reading of the report - they agree it was lit after the accident but say the track damage sustained in the derailment is what caused that effect (the twisted rail), there was no damage to the signalling side of the system.

 

PS - RAIB not HMRI

[beast66606]

Interesting... HMRI fail to take into account that the indicator was lit directly after the incident as noted by the driver, yet significant damage to the track had incurred after the derailment... Although HMRI claims the signalling system to be working correctly, there was clearly a fault with it, as the indicator lit when the point wasn't fully closed... Another symptom of the "we-must-blame-someone-no-matter-if-he'd-dunnit" culture so poignantly prevalent these days?

 

It actually says the switch rail was twisted and standing off at the top

 

This meant that the toe of the right-hand switch rail was away from its stock rail by 11 mm at rail head level.

In this condition the PSI was still illuminated,

 

and

 

When the damaged stretcher bars were removed the switch rail returned to a

vertical position. Subsequent tests on the points position detector unit found that

the PSI extinguished when the switch rail moved more than 3.4 mm away from its

stock rail. This and other tests showed that there were no faults associated with

the detection system and the PSI.

 

So I'm not sure of the point of your posting

[Kris]

Interesting... HMRI fail to take into account that the indicator was lit directly after the incident as noted by the driver, yet significant damage to the track had incurred after the derailment... Although HMRI claims the signalling system to be working correctly, there was clearly a fault with it, as the indicator lit when the point wasn't fully closed... Another symptom of the "we-must-blame-someone-no-matter-if-he'd-dunnit" culture so poignantly prevalent these days?

 

When I read the report I felt that the RAIB had taken this into account and decided that it was most likely to have been lit after the accident due to the damage to the track, and that they felt on the balance of probabilities (given that the indicator worked correctly before as noted by other drivers and after when the stretcher bars were released correcting the damage) that the indicator had not been at fault.