13-05-2008, 06:09 PM
Peter Wrote:and the other calculating the theoretical maximum length of the track circuit as in question 6 in 2007.
Hmmm, looking at it, not quite!
The calculations were right, but a bit meaningless - certainly not what was wanted for the question quoted - I had left it calculating the length of the TC at which the relay would drop with a given drop shunt which does not really mean much. Sorry for any confusion there.
Here,
TC length for relaible operation.xls (Size: 20.5 KB / Downloads: 505)
, instead is a modified sheet which gives you the steps for calculating the length of a reliable track circuit given the parameters quoted, except the question was for a TC with an additional, identical feed end relay. The model only has one relay so the parameters entered are those of both relays combined in parallel (ie 10ohm vice 20ohm and PU current of .23A vice .115A)