Placed my order Friday a.m., received my FT-A/B sets just after noon today. Inter-Mountain has again outdone themselves wih these sets. Just returned from the train room where #4017/4117 finished a few short runs for me. It appears that the A and B units are closely matched in speed but I did have to get them up to about 6 - 7 volts before I got lights and movement And apparently I-M is really following the prototype, the A-B units will be drawbar connected, can't figure out any way to mount couplers between the units. This has been an amazing 15 - 20 years. Who have thought that every iconic (at least to me) SAL diesel unit would be available. FT sets in addition to RSC-2s, SDP-35s as well as the staple GP-7s and RS-3s.