AIU "bug" or "feature"?

AIU's are essentially a Relay box. They don't have any logic in them.

They were designed and tested with Solenoid type switch engines in mind as these are more numerous in O gauge and are made by MTH for both of their track systems.

I suggest you check page 73 in Ver 2 of Barry's excellent DCS Companion. It explains how to connect tortoise type switches to the AIU using an External latching Relay.

Thanks for the tip, forgot about that solution.  However at $25 a relay times ten switches, I think it will be easier for me to remember to keep that arrow button pressed for several seconds!!

Aren't the DZ -1000s momentary type switch machines? They do have a motor (not coil) and  limit switches  that turns the motor off at the end of each throw. Only takes a momentary shot of current to throw the switch though. I believe you can add a resistor to the circuit to keep the leds   lit. 

rrman:  On my layout, I hear the AIU relays click in and drop out.  The time interval doesn't differ regardless of whether I press and hold a remote button or give it a quick press. I also have no problem with DZ1000 switch motors due to power cutting off too soon.  (I do have problems with them sticking, but that's a different issue, in the switch motors themselves.)

Gregg, yes it is motor driven, the microswitch cuts off the power at the lock limits AS LONG as power is available.  If power stops too soon, motor may not complete its travel if Ross tinplate switch points are stickey, binding or the "square" spring between motor lever and points rod is not adjusted for even tension both sides of throw. 

I just got 10 replacement sets of DZ1000 for trade plus cash from Z Stuff.  Will have to see if these are performing better than old ones.  Suppose to be a new cam design that insures full throw lock to lock without bounceback.  Time will tell after motors wear in.

Will have to see if these are performing better than old ones.  Suppose to be a new cam design that insures full throw lock to lock without bounceback.  Time will tell after motors wear in.