I have a set of Lionel MP54 commuter cars, 6-18306, that had a bulb go bad. I followed the directions in the owner's manual and removed the bulb, but was surprised to find out that although the bulb looked like an L57, 12-14 volt bayonet base bulb, it is actually a 5 volt bayonet base bulb. I searched a couple of parts houses and even called Lionel, but nobody seems to have a 5 volt bayonet base lamp. The Lionel manual doesn't mention a part number for the bulb. I put in a 6 volt bulb that's used in the 2400 series passenger cars, but it is dim because the output voltage from the regulated board is only 5 volts. Does anybody know a part number for that 5 volt bulb?