The A-3177 (LT-2500) was a
diesel-electric transfer-unit
locomotive, built by the Lima-Hamilton Corporation between 1950 and 1951. The A-3177 was the final locomotive model produced by Lima-Hamilton before the company merged with the
Baldwin Locomotive Works in September 1951 to form the Baldwin-Lima-Hamilton Corporation (BLH).
All twenty-two units were ordered by the
Pennsylvania Railroad, with the last one, #5683, completed on September 12, 1951, the day after BLH was formed. All were scrapped, with the last three being retired by 1967. The PRR ordered 22 more but agreed to receive 23
RT-624s from BLH instead.