The only exception I know to Peter's statement is the ACC Ansaldo (Italian) signalling system installed for Manchester South, where the technician form the control centre can certainly get a voltage reading of the volts across relay coil and so can get some indication that a track is likely to be about to fail due say to a combination of wet weather and poor ballast giving low ballast resistance etc.
In the UK at least I believe "this is the exception that proves the rule", although potentially I suppose other monitoring systems could be implemented as a local initiative nowadays, given the more ready applicability of reemote sensing technology.
Reuben may be able to add something.
In the UK at least I believe "this is the exception that proves the rule", although potentially I suppose other monitoring systems could be implemented as a local initiative nowadays, given the more ready applicability of reemote sensing technology.
Reuben may be able to add something.
(03-10-2012, 02:47 PM)Peter Wrote:(03-10-2012, 01:47 PM)Shomel122 Wrote: Hi,
Im new to signalling and new to the railway. Just wondering how are DC track circuit powered. What are the fault indication if current, resistance or voltage were higher than normal?
Simple track circuits do not have any monitoring as such - the voltage levels are checked on routine maintenance and assessed by the technician. There is no condition monitoring as such. If the supply fails, or drops below the required level, the track relay would drop and the track would show occupied on the signaller's display.
Peter
PJW