handling a 2,000-ton train between Colehour and Harsimus Cove. Two months after the conference, Baldwin Locomotive Works officials presented four designs to PRR: a 4-4-4-4 passenger locomotive that could haul 1,200 tons but exceeded existing weight and clearance restrictions a 4-4-4-6 passenger locomotive that could haul 1,200 tons but also exceeded limits a 4-8-4 freight locomotive with the same weight on drivers as an M1a, which failed to meet the requirements for a 2,000-ton train an articulated 4-6-6-4 locomotive PRR preferred 4-4-4-4 and asked Baldwin to consider a passenger version with 6 ft 8 in drivers and a freight version with 6 ft drivers. However, the cooperation between PRR and Baldwin, which proceeded without signing any agreement or contract for the development of the new high-speed duplex engine, didn't go smoothly. Ten months after the first conference (April 1937), PRR ended Baldwin Locomotive Work's consultation and assigned the task to a consortium of Baldwin Locomotive Works, American Locomotive Company, and Lima Locomotive Works under a joint contract. T. W. Demarest headed the joint committee, General Superintendent of Motive Power in PRR's Western Region. The members of the joint committee were: Ralph P. Johnsonn (Baldwin) William Winterwood H. Glaenzer (Baldwin) Dan Ennis (American Locomotive Company) William E. Woodard (Lima) Samuel Allen On 28 April 1937, PRR's Board authorized $300,000 for this experimental high-speed passenger locomotive project. The design started with a 4-4-4-4 duplex. On 2 June 1937, PRR officially announced the development of the “Pennsylvania Type” high-speed passenger locomotive which would become Class S1. After various details were discussed and finalized, it became necessary to make changes that substantially increased the locomotive's weight. By the time the plans were finalized and approved it had evolved into a 6-4-4-6. Duplex design The benefits of a duplex design included lighter machinery, shorter cylinder stroke, less wear, lower piston thrust, smaller more efficient cylinders, and a more stable frame than an articulated underframe; also, no hinged connection had to be maintained. Reduced hammer blows on the track resulted in lower maintenance cost. Two sets of drivers with four wheels each could have lighter (as much as 25%) running gear than a locomotive with all four axles coupled together, smaller and lighter moving parts ensured less wear and tear. Baldwin's chief engineer believed that the 8-coupled, two-cylinder locomotives of the time were at or near practical limits in terms of steam flow, cylinder efficiency could