diodes for track controlgreenspun.com : LUSENET : Wiring for DCC : One Thread
Can I use a diode (e.g. IN4001) to prevent a locomotive from crashing into the bumper stop at yard end in a DCC system?
-- Percy Leung (email@example.com), June 18, 2004
Unfortunately not. The DCC track voltage is a form of AC. This is one of those rare situations where something that was simple in DC is not doable in DCC.
-- Allan Gartner (firstname.lastname@example.org), June 18, 2004.
It really isn't doable in DCC that I know of. It can be done for a lot of money and programming. You would need a block detector, a way of sending the block detector signal to a computer, a computer with train control software on it, and a computer interface to your your DCC system. Your computer would need to be in control of the train at the time you would want it to stop.
The simplest thing to do that does mostly what you want is to have a section of track before your bumper that you turn off with a switch. When you want the train to go, command it to go away from the bumper and turn the switch back on. This isn't as slick as the old diode trick, but at least it won't cost you $250 to implement.
Note: Instead of turning of the power cold to a locomotive you could use DC braking. See the other Q&A question I just answered titled "braking sections using a Digitrax Chief."
-- Allan Gartner (email@example.com), June 19, 2004.