Guys - sorry for the delay.... been working nights and weekends and it's taken me away from this. The online documentation might be somewhere for the Viessmann product line but I can't find it. However here is what i found: the semaphore is operated by a solenoid. separate circuit for lights on the semaphore vs. the solenoid movement power (totally separate ground and throw contacts). So essentially the throw mechanism is like a 3-contact solenoid switch.
Armed with that knowledge, I found a circuitboard that works very well from Azatrax. http://www.azatrax.com/dual-train-detector.html The documentation on these boards is awesome, simple to understand, and includes several examples of operating mode implementations. You know, "when Train A is eastbound and Train B is westbound.... when will grandma's cookies be ready?" LOL. 
Seriously check it out if you have any such needs.
