I’m repairing an old 249 Lionel steamer for a friend. It wouldn’t run at all, so I took the motor apart. (Though this is a Scout engine, it does have an open frame metal motor.) Everything was filthy. I cleaned the commutator face, the brush wells, the brushes themselves (they still have life left in them), checked the springs, etc. I also cleaned out old grease and oil and relubricated appropriate parts.
The engine now runs fine in both directions, except for one problem. If it sits idle overnight, it doesn’t want to start up the next morning. It needs a push (or two, or three) and then it takes off. After that it will be fine for the rest of the day. But the following morning, same thing.
Your 249 motor is very similar to a 1615 motor. I have a few motors of the 1615, which were stiff, gummed up, etc., from years of storage. I had to do the same as you did, but I also used spray contact cleaner, sprayed on the internal parts of the motor. I had to spray and lube them a few times, before they would run consistently. My dirty motors presented the same syptoms as what you are describing. Give it a try, and see if it remedies the “No Run” situation.