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.
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?
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!
The essential things in life are seen not with the eyes, but with the heart. --Antoine de St. Exupery