Novice, need help

[nickaix]

Hard to tell from the photo, but it looks as though one wire is already soldered to the lug under the left-hand screw. 

Lionel has exploded diagrams for MPC and LTI production on their site www.lionel.com/CustomerService/service-documents ("Product Supplements" Download 1-9; your engine is on pp 3-6 and 3-7.) Unfortunately, the diagram is not very clear, but it seems to show your stray wire connecting to the solder lug on the e-unit. This would complete a circuit, since the lug to which the other wire is soldered is grounded to the outer rail through the motor frame, while the solder lug on the e-unit is "hot."  You will have to take apart the engine to reconnect the wire, of course.  Hopefully someone who has worked on more 4-8-4s than I have can help you with that (though I do remember it being surprisingly easy to do).  With any luck, the other end of the wire is dangling somewhere inside the engine, and that will tell you for sure where it should connect.

 

[TrainLarry]

The wire with the soldered end looks like it would get resoldered to the ground lug under the left-hand phillips-head screw of the motor.  The wires bring power to the tender for the Sound of Steam and whistle.

Larry

[Stourbridge Lion]

Sorry to hear of your loss...

[AquaBuddha]

Hello, one of my relatives passed away and I acquired some of his Lionel trains collection.  I want to sell the locomotives on ebay but as I was cleaning and taking photos of the trains I noticed that one of the wires on his Norfolk and Western (6-1800) tender look odd:

It looks like the white cable is connected to another cable and that cable is cut at the end.  I assume that the cut cable is supposed to be connected to the engine, and if so then I guess this would need to be repaired.  Here's the back of the engine in case you want to see that as well:

I don't really know what these cables are for and what I would need to do here.