Abstract: Trailer having a main frame with a horizontally extending deck and a pair of longitudinally extending rails spaced a predetermined distance apart for receiving flanged wheels of railroad equipment, and a laterally extensible rear subframe assembly connected to the main frame for movement between different widths for different loads. The subframe assembly has a pair of longitudinally extending rail members which can be aligned with the rails on the main frame to form an extension of those rails.

Abstract: Self-steering trailer having an elongated main frame, the rear end of which is supported by a sub-frame and steering dolly. The dolly is connected to the main frame in such manner that the dolly is automatically turned relative to the main frame in response to lateral movement of the rear end of the main frame to steer the rear of the trailer in accordance with the lateral movement. The steering means comprises an A-frame connected to the dolly, and a steering arm which interconnects the rear of the main frame and the dolly. In some embodiments, a manually controlled actuator is connected between the main frame and the dolly to permit the rear of the trailer to be steered manually.