Lionel 6-81154 engine stalling.

What kind of grade are you running? Also how many cars are you trying to pull? I have long 2% grades on my layout and I almost always need two or three locos to pull a train with 20+ cars.

Top suspect is this little 4-spoke spline slipping on the shaft of the motor.  It's pressed on, and I've had a few that have started slipping.  I used to order new motors, now I use Loctite 638 Retaining Compound to bond them back together.

I have 15 Lionel container cars an an MTH dash 9 dummy. Grade is probably 3% for 6-8 ft. I have another legacy loco that’s a couple years older that pulled it with a second dummy with very little trouble. Reiterating that the wheels are not spinning when it stalls.

Gunrunnerjohn I will see if that is indeed the problem and get back to you. Do you take it off or just put the loctite on and let it dry?

Twist the truck off, they're twist-off trucks.  If this is the problem, you can likely grab that with a small pair of pliers and pull it off the shaft.  Clean it and the shaft, and apply the Loctite 638 to the shaft and slip the spline back into it's proper position on the shaft.  The end of the shaft should be level with the top of the spline.  Let it cure 24 hours and put the truck back on.

Mine seem to be held together with a plate and 4 screws. 2 on a square plate that holds the truck to the engine and 2 screws go through that plate and the frame of the loco and into the motor.

Trust me, the trucks come off without any screws.  On some models, you have to remove the shell as the truck hits stuff hanging down, it has to twist 90 degrees.  I believe one I found that removing the sideframes allowed clearance to remove the truck without removing the shell.  On some there's also a connector on top of the truck that unplugs for the pickups and coupler, however it's not shown on your parts breakdown.

Ah yes!! Thanks John! Much easier than the way I took it apart the first time. I will go get some of that loctite and see what happens. I will check back with news. Thanks again for the help

I'd first verify that is the problem before buying the retaining compound.  It's not cheap.

I went down this morning and those cogs came off with no resistance. Also no groove for them to sit in. You would have thought they would have put a flat spot on the shaft to stop the problem of them slipping. But who am I to say? Just a Trucker. Lol

Yep, pretty common issue.  I have no idea how they expected them to stay there, but the retaining compound will bond them and you shouldn't have the problem again.

Update to the engine stalling issue. As per gunrunnerjohn using the loctite 638 worked like a charm. I did however stop with cars still down the grade and then tried to start going again and it revved up but didn’t go. Light in cab began to flash with no code. Just on off flash. I shut power off and back on and then it went along it’s merry way.

Sounds like you actually stalled the motors, that's why you got the flashing.  The rhythmic on/off flash is code 1, motor stall.

Gun runner John is that a common issues? Was doing that before I fixed the shaft spinning problem. It also shuts down sounds when it sits and idles for awhile. Then just makes light metal pounding sounds. My older legacy engine doesn’t do that.

Not sure what is happening with yours now, that's probably one I'd have to see.  Obviously the symptom with the blinking cab light and stoppage suggests a motor stall, but it may be some other issue.  There may be a wiring issue to the RCMC, or the RCMC could be flaking out.

It’s a new engine but I did put Peco led lights in for step lights and just connected to a power wire and ground that I believe was from the pick up wheel or coupler. Would that have anything to do with it? Other than that I haven’t done anything else to it. Let me know what you think.

I can't imagine the lights doing anything, but if something was screwed up while you were in there or you pinched wires, that might account for it.  It's also possible the retaining compound didn't do the job, you might check that and make sure that little dog on the shaft is still secure.

@WTAM posted:

It also shuts down sounds when it sits and idles for awhile. Then just makes light metal pounding sounds.

That may actually be normal, it's quite possible the prototype has an automatic shutdown, I haven't seen this specific engine.

Ok I will do that and check back.

FYI, the retaining compound needs a full 24 hours cure time, when I've rushed it, it hasn't always worked out.