Hi all,

I am designing a small shadow station on my analog layout without automation. In my mind the process works like this:

On one side of a loop, a pair of curved turnouts set in opposite directions and unwired such that one train always runs counter clockwise on the outside track, and the other always runs clockwise on the inside track. They are inside a tunnel so I don't want to install solenoids.

One signal each side, controlled my a human. After a train enters the tunnel, a switch is pressed, cutting off current to a track at the end of the station. Same thing for the opposite side. The locomotive stops and the entire train is inside the tunnel.

Here's the rub:

My layout is a small one, and I need to know if the end of the train has cleared its turnout so that the opposite side is clear. I'd like to install some sort of track occupancy detection system. My first thought is to use small (24107 etc) contact tracks that send a signal to a light bulb, and have an array of these, so that I can tell if a car is currently parked on a track too close to a turnout. However, I'm not sure how reliable this system is, in terms of the train car always making the required contact and as such illuminating (or not illuminating) an indicator bulb?

How can I make sure that if there is a car on the contact piece, it won't show a false negative due to a slightly dirty wheel, or any other real world happening preventing continuity and therefore indicating the lack of presence of a car, when in reality the track section is occupied?

Are contact tracks reliable in this sense?

Thank you, and hope this all makes sense.

Hi Brian

I have been a huge fan of analogue Märklin automation.
Here are the rules:
- avoid multi-slider trains and have the slider in front of the train
- have a stop section of 2 rails (36 cm) just before the exit switch
- install, slider-operated contact track just before the stop section. The rule is make sure that at no times, a slider will stop on the contact track. Use this contact to liberate the next train
- avoid using the same contact track for multiple use (switches, signals, etc). Why? Because of high currents and because of "lost independence"
- standardize the length of your trains and sidings so when a train is stopped by a signal, it has cleared the entry switch.

With all this in mind you can do an incredible number of things.

The limitations:
- you end up having quite a lot of contact tracks
- trains with multiple sliders (lighted coaches) are really a pain in the neck
- safety is limited, assuming wagons never uncouple, etc

Cheers
Jean

Yes, this is true, I can confirm. When I set up one analog slider switch with M-track to fire both a switch and signal, it often would misfire and not switch both of them.

Having lots of contact tracks well placed and as you say do not let them stop over the contacts for fear of burning out the solenoids. We always were reminded of it when we forgot or stopped trains in an irregular location and you would hear the buzzing of the solenoid still going.