I have spent some time over the last two days fitting a lighting kit to a Bachmann class 20. The wiring up was complicated by the fact that it has sound fitted (reblown by Howes), a bass enhanced speaker and a pair of wires leading to a two-pin socket which allows a second, de-motored class 20 with a larger bass reflex speaker to be semi-permanently attached.

The lights include separately wired marker and tail lights at each end plus a cab light. The sound decoder is an ESU LokSound with only four external functions for five lights. I wired the nose-end marker lights (i.e. the headcode disc lights) and cab-end tail lights together, auto-reversing with just the tail lights at the nose end, so that's two functions used.

The marker lights at the cab-end are wired to the aux 1 output, F11 on the decoder.

The cab light is wired to the aux 2 output, F12 on the decoder.

To run with the nose end leading there is no choice in having the tail lights showing at the cab end if the leading marker lights are lit. Other than that, leaving F0 on but hitting reverse so the cab-end is leading results in the nose-end tail lights coming on; pressing F11 turns on the cab-end marker lights. Turning F0 off leaves the marker lights on F11 turned on but means there are no tail lights showing, for use when in multiple or hauling a train.

Overall, I believe I have achieved the maximum versatility/best compromise from having five lights on four available functions.

The class 20 has been lightly weathered and actually has a cab swapped from another disc headcode model where I had modified the side windows from the original Bachmann recessed sliding ones to being flush mounted but fixed. It was renumbered to D8058 with the earlier style numbers (as per a photo of the real locomotive).

The lighting kit came from an eBay seller under the name of Stickswipe, who was also very helpful.