Also very helpful for me. I have an ancient Lionel 249E loco that was given to me 60 years ago. Never worked, so I decided to take it out of storage and try to get it working. Realized many parts missing...including the brushes! The e unit was also a mess. Called Brasseur Electric Trains, and they said to send in the e unit and they would get it good as new. They did!! Returned completely refurbished e unit along with the brushes.
Installed the components, and the unit began to move for the first time...in reverse only!! Switched the yellow and green wires, and moves in forward only. Could not figure out how to wire this correctly.
Then saw the diagram above with the colored wires. I reversed where I had the green and blue wires connected and bingo - works in both directions!! Christmas came early!
Now I just have to find a front truck assembly and one of the cross bars, and I have a functional 249E.
Many thanks,
Michael