Ill take a stab at your question dude. On most units the drawbar will return to center in the pocket, on units without "alignment control couplers" the drawbar can be shoved (not centered) all the way over as your going down the tracks.
Assuming i know what im talking about here: UP SD 40-2 yes, old SW1500 switch engine no.
This might help you out.
=================
Union Pacific Rules
LOCOMOTIVE AIR BRAKE TESTS AND INSPECTIONS
31.17.2: Locomotives Not Equipped with Alignment Control Couplers
Most SW1200, SW1500, MP15, GP7, GP9, SD7 and SD9 locomotives, waybilled locomotives, some foreign line road and switch engines, some Amtrak and other commuter locomotives are not equipped with alignment control couplers. These units may be identified on the train list. They are to be placed second in the locomotive consist, one per train when handling cars.
Mechanical inspection forces must ensure that coupler swing limiting devices are in place before these units move in freight trains. Coupler swing limiting devices do not make the coupler an alignment control coupler.
Updated: 12/09/2004
=================
Union Pacific Rules
LOCOMOTIVE AIR BRAKE TESTS AND INSPECTIONS
31.18.1: Locomotives Equipped with Alignment Control Couplers
Shut down locomotives that are not equipped for multiple-unit operation or have inoperative multiple-unit equipment and couple them directly behind the locomotive consist.
Locomotives that cannot be determined whether equipped with an alignment control coupler, must be moved as described in 31.18.2 (Locomotive Not Equipped with Alignment Control Couplers).
Updated: 12/09/2004
================
Union Pacific Rules
LOCOMOTIVE AIR BRAKE TESTS AND INSPECTIONS
31.18.2: Locomotives Not Equipped with Alignment Control Couplers
Locomotives that are not equipped with alignment control couplers may be identified on the train list. They must be shut down and placed not less than five cars or greater than ten cars from the rear of the train, with at least one car separating locomotives. No more than two locomotives may be placed in a train.
Mechanical inspection forces must ensure that coupler swing limiting devices or truck bolster movement limiting devices are in place before these units are moved in freight trains. Distributed power consists or manned helpers must be cut in ahead of locomotives not equipped with alignment control couplers.
Place locomotive with bolted or temporary drawbars no more than five cars from rear of train.
Updated: 12/09/2004
=================
Union Pacific Rules
LOCOMOTIVE AIR BRAKE TESTS AND INSPECTIONS
31.17.1: Locomotives with Alignment Control Couplers
When a locomotive equipped with alignment control couplers is being placed in a train with the diesel engine isolated or shutdown, couple the locomotive(s) directly behind the locomotive consist at the head end of the train. Then, do the following:
Set up air brake equipment as a trailing unit, couple all hoses, connect MU jumper cables and open all cut out cocks between the operating locomotive consist and the units that will be moved.
Perform an air brake test as outlined in Rule 31.6.2. (Conducting Locomotive Air Brake Test.)
Exception: SW and MP model switch engines must be placed second in the locomotive consist, one per train, when handling cars.
If it cannot be determined whether a locomotive is equipped with an alignment control coupler, locomotive must be moved as described in 31.17.2 below.
Updated: 5/03/2005
