As a modeler, what’s the difference between an EMD E3A, E5A, and E6A?

I want an E3A and E6A (N scale) but the only thing I can find is the Kato E5. I have decals for both the ACL Campion E3 and IC City of Miami E6, but neither appeared to use the E5. I’ve read the primary difference was electrical but the Kato E5 appears slightly different.

Anyone been successful at getting these cars to run well ?

Ive added weight to the trailers and am experimenting with modifications to the truck under the hitch by removing the front screw and trimming some plastic away to allow some ability for the B end axle to swivel slightly

Hi all, I'm hoping to get some general prototype information from those of you that know more about railroads and how they hauled salt. I've lived virtually my whole life in North Carolina, where it snows very little except in the highest of mountain elevations. I am interested in learning more about how the railroads hauled salt for use in spreading on roadways. I am planning for a future HO Scale, 2' x 20' northeastern U.S.

 Any suggestions how to build a drive shaft that does not slip? 

I am trying to re-power a loco with a small can motor, 1.5mm output shaft. The NWSL sockets on the motor and the worm shaft do not slip.  I built a drive shaft from brass rod and the 1.5mm ID balls included in the kit.  The balls slip on the shaft under torque. I knurled the shaft.  They still slip. 

What I did: