I have Northern that is several years old which doesn't get operated much. Yesterday, I had it out and it was running fine. Then it made a station stop but would not proceed afterwards. The head light comes on, but no motion, the drivers appear locked.
I was going to tear it open to see what went wrong, so I went to get the instruction sheet and found it has a Lifetime Warranty.
So what's the next step?
Bogie
It will cost you $40-$50 for a DCC Upgrade if your loco does not have DCC and is not fixable, otherwise it will cost $25 for service and whatever shipping is one way (approx $12-$15). But, wait to see if you can fix it before sending it off, because it won't come back until sometime in February now that it is close to Christmas.
Considering the shipping, mine was done in a weeks time (7-10 days)
I don't know if your northern is old enough that it has the old pancake motor. If it is, I found that you can take the shell off and lift the mental spring that holds the brushes down. and just let it snap back. Just don't lift it too much.