Proto 3 changes??

All proto 3 locos have DCC/DCS capability.  The switch was included in most, if not all premier engines, and was added to later some railking locos.  Later boards have EMI protection, mostly to meet European standards, but function the same.  The boards always had capabilities to do a lot of things; the added features were mostly hardware (smoking whistle, chase lights, quillable whistle) and DSP code to operate them.

Jon G 

I have a UP Railking Aerotrain catalogued in 2011, vol. 2 as a PS 2.0 engine but delivered in 2012 with PS 3.0. There's a slot at the side of the frame labeled DCS/DCC but it's empty with NO switch! If this engine is DCS/DCC capable as you say, how can I choose between those two systems if MTH hasn't included a switch to select either DCS or DCC?

**Btw, to make it able to easily pull a prototypical 8 car Aerotrain consist (7 coach cars and the observation) I had to add 20 ounces of weight to that engine's shell because the way it came from the factory, (even with two motors,) it couldn't pull more than the three cars that came in the set plus an additional add-on coach car.

I only hope that over time and prolonged use the engine's two motors prove capable of handling that extra 1-1/4 pounds without straining, taxing, overheating, or in any other way being detrimental to them.)

If truly Diesel PS-3 should have switch.  If not, pin 1/40 wires are attached together (possibly with wire nut).  When open DCC, when wires connected DCS.  Look at the PS-3 diesel instruction on the web to see.   G

Some Diesel engines had the slot for the  DCS/DCC switch but the slot was empty (no switch).  The engine was set to go automatically to DCS.  If you wanted to run DCC, you had to open the shell and cut the grey wire.  You then had DCC but no longer DCS.