Keal.....I see your Loco has the early TMCC LCRU board in the engine so it should work fine with a original 14 volt bulb. How about replacing with a new one? Here is the bulb from Lionel $2.00 but their postage will be much more than that. Also if a wire burned that might need to be repaired. Looks to me like the boiler front can be removed with one screw.Take a look. A led needs a resistor and diode added. Since you are not in to soldering perhaps one of the vendors shown above could help.
6101449300 | LAMP / 14V 0.3A / CLEAR / SCREW BASE |
https://www.lionelsupport.com/...72-9cf0-1491792dd2e9
Richard