Where to connect a keep alive circuit to a DCC Sound 0-4-0 Porter?

I'm building some keep alive circuits for my critters. The circuit will be housed in a separate tender with pickups on the wheels.

So I have a couple of questions:
1. Where would be a good place to connect the keep alive to the decoders on a sound 0-4-0 Porter?
B. What sort of pickups are available, or ones maybe you have built, for the tenders?
Paul

 

it depends on the decoder you have ... most do not have keep alive wires on the outside ...
chances are that you have to take off the shrink wrap, and solder directly to the decoder pcb..
if it matters, you don't need pickups, the keep alive draws power from the decoder pcb ..

 

Of course it does, silly me duh.......Thinking that electrical engineering collage might have been wasted, course it was nearly half a century ago

 

Using Bachmann HO bobber cabooes as a platform for the keep alive circuits.

 

Hookup to a DCC sound 0-4-2 is easier and here is on with my hi tech camera mount.

 

Video test:

 

This is what happens when you forget to set the DC mode to off and disconnect power from the track: