SD70Ace UP, Banking COMM, Reversers Unsynchronized Consists with Distributed Power. Banking COMM on in Lead Unit, off in Rear Unit. Reversers synchronize initially at startup. After the Throttle is moved in the Lead Unit, the Reverser in the Rear Unit is stuck in its last position. Can be fixed by turning Banking Comm off and back on in Front Lead Unit. This is unnoticeable initially because the Reversers are in the right position. It only becomes apparent when Rear Unit is stuck in neutral because the Throttle was moved before the Reverser. Or changing direction, Lead Unit in Reverse, Rear Unit stuck in Forward (Cabs facing same direction). Rear Lead Unit stuck in neutral, consist doesn’t have enough power, and no dynamic brake in Rear Lead Unit. Observable from the window of the Rear Unit. Repeated this with various SD70Ace UP consists with Rear Units (Banking COMM, Distributed Power), both on Sherman Hill and Sand Patch Grade.