Acton area signalling problems

[xtmw]

I've noticed for the past few days both North and West Acton stations have been having signalling problems? What seems to be the issue? Do they just keep failing or is it something else?

[Dstock7080]

4 October signal NOA2354(1) failed for one train, points set for Ealing

5 October 18:00 Track Issues West Acton
Continued track issues services reduced to allow Track Team and ERU to investigate. Service suspended North Acton-Ealing 18:55 to carry out track investigation. Following investigation rails contaminated by Sandite, scraped but not resolved issue.
Resumption of service to Ealing Broadway. 21:00, 125 minute service suspension.

10 October 10:12 Track Issues West Acton
All trains to pass through area under failure conditions.
Track Team on site report large field of Sandite debris.
the field of contamination is too large to deal with during traffic hours. All trains to apply rule in the area until close of traffic with full investigation overnight.

nothing reported on other days.

[rincew1nd]

Interesting, especially given that sandite contains an ingredient to aid track circuit activation.

[Tom]

It's not good in blockjoints though!

[jimbo]

Does Sandite have a metallic component to aid electrical conductivity? So it aids track circuit detection of train wheels on crushed leaf contaminated rails. But it can also provide alternative paths around block joints which can break down the signalling system operation! Is that why the outer Met. has used a system in Autumn to check on consecutive track circuit operation?

[Chris M]

Yes, Sandite does have a metallic component - Network Rail describe it as a mixture of sand and antifreeze that also contains steel shot. Sand itself is also a terrible conductor of electricity, so without the steel it would likely make the reliability of train detection even worse!