Hi Peter: Thanks for your article and information.
"The NWSL motor replacement was a slight improvement, but in retrospect not worth the cost." I have quite a bit experience in repowering, and it appears to me that the the motor used is too small for the heft of an S scale locomotive and components that engine will be carrying. I suspect it will need much more torque at lower RPM than can be produced by that small motor. For example: I recall using Mashima 18 x 33 flat cans in HO GP diesels with satisfactory performance when mated to improved Athearn 4 wheel truck assemblies. In contrast, a Sagami 1630 did NOT work as well using Athearn trucks on account of the 12:1 ratios (I think that was it) in the Athearn 4 axle truck assemblies. Again, not enough torque at slow RPM. "I think, ultimately, at fault is the gearing in the AM gear tower (it has the "low" gear). It appears from the pictures that you have the later style power truck assemblies. My box-stock AM FA also has the later style truck assemblies, but it still doesn't quite approach the smoothness of all of my S-12's. As yet, I have not set about to determine why. My FA (as does yours) appears to use the same truck assembly as my S-12's, so logic would say that my FA can be made to run as good as my S-12's with some tinkering. My AM GP9's are a different matter. They use the earlier truck assemblies and they will need to be significantly improved before I will be satisfied with them. Have you disassembled your AM FA trucks to look for obvious issues? i.e. Cracked gears, tight mesh, binding worm, etc? Andre
