Wheels locking up on 0-8-0 steam engine

Top suspect is the rods either hitting the screws or a wheel is somehow out of quarter.  Make sure all the rod screws are tight and the rods aren't bent so they will catch one of the screws.

With the motor out but the rods installed on the wheels, slowly rotate the wheels and see if you feel any binding.  At the point you feel a bind, see which rod is tight, that's probably where the issue lies.  The rods on either side of the locomotive should be 90 degrees apart, if a wheel has slipped on the axle, that can cause a lockup.

Many times its because the eccentric crank has loosened and is out of place. It should be pointing just off center of the axle. More than that and it will try  pull or push the eccentric rod further than it can reach so the wheels bind.

Pete

I would take out the motor and see how well the loco free rolls without the motor gearing. A bind in the mechanism, probably side rods, will show up. If you suspect a bind in the side rods or valve gear, you'll have to sniff it out.

Good luck!

Thanks for that idea, I am on the same thought, I took all the connecting linkage off and motor out, all 4 sets of wheels turn freely , greased all of that stuf up while it was apart, put the bar in that connects all 4 together and no issues, thinking it's the little piece that goes from the main drive wheel to the very front, it had a bow  on the one side and with those disconnected it has been running good in both forward and reverse, so may see if they have in stock at MTH but doubt they will. They did have the little 10 pin connector on the little PC board where the tender connects to the engine, I replaced that today as well along with rear trucks on tender

You shouldn't have to replace the eccentric if it still has its tabs that fit into the wheel. Just straighten the rod and locate the eccentric in the wheel facing the axle until you feel the tabs lock into place.

Pete

Well after debating on taking some of the linkage out of equation I slowed down and kept checking things and found that one of the bolts that connect the linkage onto the main drive wheel was backed out just enough to allow the cam holding the one small linkage to slip and when it grabbed again it was on the top of the main drive wheel and that is where it got all jammed and locked up. I had taken another motor out of an engine that I was having issues with and the worm gear looked the same but apparently is a bit different because the engine runs a little slower when set at the same speed, I have a puller on the way so I plan on changing that and the real fun thing was learning about the tach chip that controls the speed, and the placement of that chip, which I learned from you guys on this forum, so thank you all.

Now I need to find out why rear coupler isn't working, the engine makes the sound but coupler not opening, tried resetting features and also did a factory reset as well and nothing, but that will be another day. For now I'm really happy I got this engine going with a motor swap and linkage fixed, it holds a special for me  since my Father and Uncle both retired from that RR outside of Pittsburgh .

once again Thank you everyone for your help and I'm thrilled to now be part of this community.

Thanks, I did exactly that and the 5mm bolt that had backed out just enough to allow that to get unlocked and then lock back in at the top and bring everything to a dead stop and in turn burnt the motor up, I straightened out the arm ( it had a bow in it when that happened )  and lined everything back up but at that point trying to get another motor was the fun part, thankfully I had one here with issues so I could grab that motor, I have learned a lot off this one issue happening.

I had wanted this particular Engine because of the RR and some Family history and was told it had been on a display for some 14 years, I'm guessing its history wasn't spent on a shelf  but that's not a problem I enjoy the challenge and enjoy the learning curve with something new.