Soldering is not too hard. One wire goes to the solder blob at the base of the bulb, the other goes to the brass threaded piece. I’ve rewired all of my J&S coaches with LEDs, which isn’t very hard either. I use a circuit in the baggage car, wire the cars together with plug in cables. The power comes from the track using stock Bachmann passenger trucks and LGB cylindrical pick ups that fit right in the Bachmann trucks. The LEDs are mounted on 14 gauge wire running through the clearstory.
I’ve got a circuit diagram, etc. Reply directly if you’d like more info. I put a bunch of info about this om My Large Scale. Look for a thread about Bachmann Jackson and Sharp cars. If you’re not too far from Sacramento, CA, come to our March SVGRS meeting. I’ll be putting on a show about LED car lighting.