This one puzzles me. Nearly all my recent purchases of steam locos--and they are many--run faster and more freely in reverse. This includes Mallets, Northerns, 2-10-2s, Berks, Consols, Mountains, Mikes, even an old Con-Cor Hudson. Any theories?
I don't know, but it's the same way in HO Scale. At an Operation Session a month ago, i was assigned an Extra with a Bachmann Consolidation at the point. I barely chugged along with 9 cars. Did my switching by hand since it wouldn't do much switching. Ended up leaving the place I was switching with 22 cars. I thought for sure I'd have to call for the helper crew. I ran around the cars tacked on my cab and coupled up. Man that sucker pulled those 22 cars up a slight grade back to the main yard with no problem. I may never know why but That has always bugged me.
Yes, sloppiness in the gear train. Running forward the worm pulls the armature forward, running in reverse it pushes it back. Since you are driving two trucks on a Diesel, you don't have this problem, as there is usually a universal joint between the motor and worms. BTW, I have not had this problem with my MDC's, nor my MP Pacific, what little I've been able to run it - it won't negotiate my curves.
My MDC 2-8-0s have many hours of NTrak run time, forward only. After all that running, they do seem a little stiff in reverse. I was impressed when they were new becaise the mechanism was as close to bi-directional bliss as any N Scale steam loco I have ever seen. I wonder if the isolation of the motor in the tender removes those thrust forces? The drive shaft to the worm has to be in at least two pieces. I bet the thrust containment is all in the loco half, and the tender just has to spin the shaft. But in all the time I've had mine, I have never had to take one apart. So I'm only guessing.
even large scale live steam engines usually run better in reverse. however, it can be fixed by adjusting the valves.
Thirdrail Keep running the MP Pacific. It will improve after about 25 hours- It now pulls 7 on 9/3/4 before slipping and at what I consider slower speeds.
And I thought it was because the engine was too light, not balanced with the motor in the cab. Needs balancing weight in the front.
