I've been putting my MTH 4-8-8-4 Big Boy (1998 PS1) to the test to see how many cars it can pull. I currently have mostly postwar (1945-1969) Lionel cars which roll harder than newer products. I'm finding that 30 cars is about the limit before coupler pull-aparts become a recurring problem. I lube the metal wheels and axles sparingly, and maintain coupler alignments to avoid height mismatch. I put lighter cars towards the end of the train, naturally.
I have a floor layout generally around the perimeter of a 23'x 23' room, 054 curves with 072 easements, conventional old 3-rail track. One 90 foot circuit around the room has three straight sections about 20 feet long each, one horseshoe curve, 720 degrees of curvature. It's flat except for a short 2% grade about four feet long, about one inch climb (over the bottom sill of an interior wall), in the middle of a 20-foot straight run. "Bowstring" derailments are infrequent on this layout, with a train up to 30 cars.
I found that the old die-cast Lionel couplers typically have a horizontal parting line in the middle of the coupler pulling face, which tends to make couplers gradually pull over-and-under on a hard pull. Careful filing with a small jewelers file to flatten the coupler pulling faces will diminish this problem.
The sheer weight of the cars and the older wheelsets make for a hard pull, and I don't want to push the engine much further. I'm using old RW and LW transformers, no ammeter. Also wonder how much abuse the traction tires can handle.
Newer (after 1969) Lionel cars and plastic trucks with pointed axles typically roll much easier, so I want to get more of those for my long train experiments.
My 1951 Lionel 2343 F3 loco with dual motors and magne-traction has pulling capacity similar to the Big Boy, it seems.
I would be interested to hear the experiences of others in this area. I've been in HO for decades, heavy-duty O gauge 3-rail for just a couple years.
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