I have a Bachmann Harry Potter HO set and would like to add lights to the 3 passenger cars. Any ideas where I can get the lights and trucks?
Because the passenger cars you have are British Rail Mk1 coaches in 00 scale you will have to do searchs for English model rail suppliers in North America or in England. I added lights to my sons MK 1s with a few LEDs, 9 volt battery and a micro switch under the body. They will last for ever and there is plenty of room in the coach for the battery and the extra weight helps.
jh-
You can freelance LED lights with batteries and a reed switch (directions in several online locations) or buy the Easy Peasey prefabs. Do-it-yourself is inexpensive; EP is beaucoup bucks. I recommend DYI.
-- D