E-unit

If you've converted your loco to a modern DC Can motor why not upgrade what's in the tender too? Replace that old clunky Gilbert reverse unit with an economical Solid State Electronic unit. Lionel's E-unit part # 610-0103-100 available at most service stations for $13 msrp. It fits nicely in the tender with double sided mounting tape and will run most DC can motor engines without the need for heat-sinking the transistors. If you feel the need to heat-sink it keep the two pairs of transistors isolated electrically. I would use two separate heat-sinks. one for each pair. A couple of Radio Shack 276-1363 should work fine. You can add a reverse lockout switch if you need one Radio Shack 275-406 but it is not necessary. Just snip off the Blue and White wire or tape them up if the switch will not be used.

Here is a Wiring Diagram.