"lost" trains

[keithm@commslab.gov.au (Keith Malcolm)]

with regard to trains, light engines etc "disappearing" from track diagrams, I 
wonder if the sensitivity (or shunting) of track circuit relays might be 
significant?

Perhaps shunting of the track by wet dirty ballast could cause false operation 
of signals and "corrective action" involving reducing the sensitivity of the 
relays might result in "lost" trains or intermittent false operation of 
signals.

Also, is it significant that such events appear to occur (in NSW at least) in 
the electrified area? (Perhaps there are no track circuits outside of the 
electrified area - I wouldn't have thought that to be the case.)


Keith G Malcolm
23 Dec 99