On 11/28/2014 10:35 PM, Mike Stein wrote: > Well, gee, if you're going to use a DPST pushbutton anyway, then all you > need is a single impulse relay like the original suggestion. Anyone remember Lionel trains? The power packs were AC (not DC as in HO) and there was an impulse relay for reversing called an "E-Unit": https://www.youtube.com/watch?v=C3cHF_a6CNM --Chuck