Sorry, but you testing method might be flawed.

Lionmaster articulated engines have 2 motors- BUT- only the rear motor provides feedback RPM via tachometer to the control circuit. BOTH motors are given the EXACT same voltage/power.

So- knowing that- if you apply drag to the front motor it does not increase power/torque to compensate. Exactly opposite, when you apply drag to the rear wheels with the tach feedback- the controller- seeing the decrease in RPM turns up the power to BOTH motors and the front may speed up, when you load the rear.

It's not broken.

Don't fix stuff that ain't broke!

Also, another thing that can go wrong is the motor coupling. It can come loose on the motor shaft and that could explain slipping.

https://ogrforum.com/topic/lionel-can-motor-question

Loctite 680 is a recommended fix.

Vernon, thanks for the reply. I have pretty aggressive inclines on my layout. When pulling a consist the engine will stall. The back drive will spin and the front drive will not turn at all. I do not have this issue with the other Lionmasters. They will pull up the incline with ease. I have cleaned the track and put new tires on the engine. Not sure what else to do.

Also, that's an internal Lionel manual number- NOT the product number.

Just saw your other post. I'll have to check out the coupling.

@Lantom posted:

Vernon, thanks for the reply. I have pretty aggressive inclines on my layout. When pulling a consist the engine will stall. The back drive will spin and the front drive will not turn at all. I do not have this issue with the other Lionmasters. They will pull up the incline with ease. I have cleaned the track and put new tires on the engine. Not sure what else to do.

Well, in troubleshooting the situation, run with the shell off and use a marker to make a mark on the flywheels and observe operation under load.

If the front motor spins at mach2 but the wheels are not- suspect coupling failure.

If the motor is weak- replace the motor- again it's getting the same power as the rear.

Will do. Thanks again.

I did the tests. There isn't any slippage between the motor and the coupling, Maybe a weak motor as you suggested. Here's a video to show the issue.

Have you ran it with the shell off and confirmed at that point the front motor still has power. I’ve seen cold solder joints or bad wires twisted just the right way and you loose connection but on the bench it’s hard to duplicate

I did test it on the track with the shell off. I checked the wiring and didn't find anything. It always stalls at the same places on the track. If it was a loose wire or connection I would think it would be intermittent. But having said that, this is a new problem for me and I'm certainly not an electrical guy.

@Lantom posted:

I did test it on the track with the shell off. I checked the wiring and didn't find anything. It always stalls at the same places on the track. If it was a loose wire or connection I would think it would be intermittent. But having said that, this is a new problem for me and I'm certainly not an electrical guy.

I have to stress this. Even seeing the video- you MUST understand that if the rear set of wheels goes into wheelslip- this causes the motor driver to TURN DOWN the overall power to the motors including the front motor. This is simply how the limitations of the single motor driver and 2 motor systems with tach exists. The set of wheels with the tachometer MUST have absolute traction grip on the track and must almost never slip. If they do slip, this only makes the problem worse because again, when they slip- the total drive power drops to only enough to maintain the rpm on the set of wheels slipping- hence stalling the engine.

I'm very concerned you are chasing a problem in the engine- and not saying it could not be the engine- but what I'm saying is, that engine and this grade are not working because the rear engine section is unloading traction wise. For so many reasons, the grade and the easement into the grade, any undulations in the track from perfectly straight- details about the rear trailing set of wheels, condition of traction tires on the rear driver set- again you are worried about the front stopping, but what you need to be worried about is the rear not gripping!!!

If you want to perform a test- turn off odyssey speed control function per the manual. This engine appears to have the Odyssey ON/OFF switch, so turn it to OFF.

https://www.lionelsupport.com/...ts/6120711149250.pdf

By doing so, this then means the tachomer feedback is no longer interacting, and throttle is just constant power. If it runs the same grade without stalling with Odyssey OFF- there is your answer- you have a traction problem.

Thanks for the detailed explaination. I think I understand it now.

This is an interesting thread.  I understand what Vernon is saying, but the original poster said that he had older versions of this loco that didn't exhibit the same problem.  Assuming that the older versions are mechanically identical, it comes down to the electronics/programming.

Thinking aloud... what would happen if Tom moved the motor with the tach to the front set of drivers (and why didn't Lionel do it this way in the first place?)  Also, what would a Cruise commander do in this situation (since it's not tach-based?)

@Ted S posted:

This is an interesting thread.  I understand what Vernon is saying, but the original poster said that he had older versions of this loco that didn't exhibit the same problem.  Assuming that the older versions are mechanically identical, it comes down to the electronics/programming.

Thinking aloud... what would happen if Tom moved the motor with the tach to the front set of drivers (and why didn't Lionel do it this way in the first place?)  Also, what would a Cruise commander do in this situation (since it's not tach-based?)

I can't imagine that the result would be different, perhaps occurring in different layout locations if you moved the tach to the other motor.  The real problem is that either truck can lose traction and when the tach controlled motor loses traction, the torque of both motors drops to near nothing.  This is a basic fault of the design with only one motor having the tach.

The obvious reason that most scale articulated steam doesn't experience this issue is there is only one large tach controlled motor, so if either power truck has traction, things keep rolling along.

We'd probably have to know more about the "earlier version" of the Big Boy to intelligently comment as to why it might not be having the same issue.  Truthfully, I've worked on the older TMCC Lionmaster Big Boy, and it's Odyssey control has exactly the same issue.  In that model, the Odyssey tach reader is also on the rear motor, and you can do the exact same thing on the front power truck and get the same reaction, the wheels stop with any pressure.

The one thing that could be an issue is the pilot trucks somehow lifting the drivers off the track.  This can happen if you don't have proper easements at the beginning or end of grades, something that bit me in previous layouts at times since I didn't have enough room (I thought).

Ted, that's a good question. Both engines have odyssey speed control function. The old one is TMCC and the other is Legacy.

I did put a stiffer spring on the pilot when I first got it (20 years ago). I'll try the same thing on the newer one and see what happens.

Update: I added a stiffer spring to the pilot and mixed and matched different tire thicknesses. It is much improved. John, your comment about proper easements set me on the right path. I have a small, challenging layout. That particular area is at the top of a helix hidden in the mountain. I may try a few minor adjustments to that area, but with all my other equipment running fine through there I have to be very careful.

Thanks to all who kept me from going down the rabbit hole!

Makes sense, glad you're on the right path.  It's a path I've already taken, several times in fact.