I pulled my newly service Lionel 6-82768 C&O Allegheny #1604 out to verify it had been repaired.
The engine runs fine from speed step "1-22".
At speed step "23", the engine slows down and acts like there is binding in the drive train. The front articulated drivers will derail at switches if I raise the speed to step "60" or higher. It appears that the front articulated drivers are moving at a slower speed than the rear drivers, causing them to be shoved through the switch frog and derailing. The engine moves very slowly at all speed steps, increasing slightly, but something is definitely wrong.
The engine did suddenly speed up at first when I reached speed step "110". At "110" speed the dragging effect stopped, and the engine began to race around the layout. Now I can no longer get it up to speed step "110" without it derailing at Atlas O-72 switches.
I checked all traction tires and brake shoes for drag or rubbing. There is clearance on all drivers. The traction tires look fine.
The front drive shaft does show some wobble as it spins, but it is moving.
Can the computer board control motor speed individually for each of the two sets of articulated drivers. The engine returns to normal when I lower it to speed step "21". The results are consistent. It starts dragging at speed step "23". It returns to normal movement at speed step "21" or lower. I have repeated this fifteen times with the same results, at the same speed steps:"23" or higher-drag and "21" or lower-return to normal.
The original Lionel service was for pinched wires in the nose of the engine that caused a short and tripped my ZW-L transformer. Maybe the board was damaged. The technician also worked on aligning the white side trim by the Cab. It looks very good now, but won't run correctly.
Do you have any suggestions?
Sincerely, John Rowlen