How do I wire in current type detectors on a DC Cab control layout?

Model Railroader Layouts and layout building
1

I have a DC layout wired for 2 cab control using common rail return and manual switches with centre off. I have used Twin T and optimised detectors before but I’m not sure how to wire them in to each block and not have them interfere with each other. (I have about 10 blocks on a 10ft by 6 ft layout).
Both these detectors need a bleed or bias resistor to detect trains when the block is no under either cabs control.
thanks
Alan Jones

2

Alan;

You need to provide some power to the block at all times for current type detectors to work. The detectors are looking for a voltage drop across the sense resistor, no current, no voltage drop.

3

Thanks Nigel,
If I wire the detectors into the feed to the track from the cab selector switch, where do I put the resistor to allow some current to flow? I assume the resistor is a high value so the train doesnt move.

4

Alan;

It would be MUCH easier and less expensive to go with DCC - still using the detectors you have.

The sense resistor is in the detector.

With DC, you could put high frequency AC on all the track at all times, which would give you the power…but this is not the easiest thing to do either. Putting a low level of DC on the track at all times is not particularily good or easy either.

5

Thanks again Nigel