If you are running an automatic shadow yard using circuit track, s88 and CS2, the pick-up shoe from the locoomotive will trigger the "finger" on the circuit track, thereby sending a signal to CS2 via the s88 decoder. How can you prevent triggering "false alarms" when you have cars behind the loco with their own shoes (IE. lighted passenger cars).

I think a solution would be to program the CS2 in such a way it deactivates the circuit track after the loco has passed. Another circuit track, a little further down the track, will trigger a re-activation for the next train. But I would like every body's input.

On another note: How does a contact track work exactly. I know that one of outer tracks is electrically insulated and the wheels reconnect the two rails thereby creating a signal for the CS2. If you install these in a shadow yard, would the insulated section be the entire storage track length or just a smaller section.

Just trying to get my head around the technology.

Thanks all!

Hi Steven,

Look here:

https://www.marklin-user...c-in-shadow-station.aspx

for what I did to this problem, following the suggestions of Jacques.
About contact tracks: I use only one track piece 24188 - works very much the same as a circuit track.
I believe Märklin recommends two track pieces for a contact track, but I don't think that's necessary.

By the way: getting your head around the technology is great fun - especially if you get the reward of success!

Steven,

That's not exactly how it works. The signal to the S88 is either ON or OFF. When the first wheel hits the contact track it is turned ON, and it stays ON as long as there are wheels on the contact track. Only when the last set of wheels leaves the contact track, it is turned OFF.

With CS2 you can program a route that is activated either when the signal is turned ON, or when the signal is turned OFF. That is, a route can be triggered when the train arrives at the contact track, or (another) route can be triggered after the full train has passed the contact track. Example: if you have a contact track in front of a station, you can have a route that turns on the lights at the station whenever a train arrives. And you can have another route that turns these lights off after the train has left.

But this simple logic can go wrong, dirty wheels or dirty tracks may cause an interruption: no more contact between the two rails, therefore the S88-signal is turned OFF. The next car in your train, with clean wheels, may turn it ON again. This causes unwanted triggering of your routes, ans that's why this "interlocking safety logic" comes into play.

Best way to go for you, if I may suggest, is to start with a very basic setup as the example with the station lights. Well, that's how I did it... And then you work up to more sophisticated things: a small shadow station, a small shadow station with interlocking safety, a large shadow station, multiple large shadow stations...

Correct.
Disadvantage of longer contact sections is, well, that they are longer. In a shadow station you want to be max efficient for space - longer contact tracks may force you to run shorter trains.




In post #3 you see a reference to another thread in which I learnt about that. The basic idea is that the cable between contact track and S88-module is interrupted by a K84, which can be switched ON or OFF. This will ENABLE or DISABLE the contact track, preventing any risk of unwanted contacts / unwanted triggering of routes.