was led by H.H. Lehman (Fireman), C.J. Wappes (Road Foreman) and Frank Ritcha (Engineer). Due to its gigantic size, the S1 had to turn on the Chicago, Burlington and Quincy Railroad's wye at Chicago before going eastbound and was unable to go through the 130 lb switch (No. 8) just to the west of Pittsburgh Union Station. This problem wasn't fixed until 1946 (which also prevented the PRR class T1 operating through Pittsburgh). The S1 was so large that it could not negotiate the track clearances on most of the lines of the PRR system, in its brief service life it was restricted to the mainline between Chicago, Illinois and Crestline, Ohio (283 miles/446 km). It was assigned to the Fort Wayne Division and based at the Crestline engine-house. As such, the S1 had to be turned on the wye at Crestline whenever it was in town, and suffered from repeated derailments as a result. Based on photographic evidence, the S1 hauled the Broadway Limited (New York to Chicago) and Liberty Limited (Washington D.C to Chicago) in the first few months of its revenue service, and was then assigned to haul other popular, heavier and commercially successful passenger trains such as The General, The Trail Blazer and The Golden Arrow on this route. Monthly mileage reports from the Hagley Library indicated that the S1 racked up per month, equivalent to twenty round trips between Chicago, Illinois and Crestline, Ohio, which in Aug 1941 was a very spectacular figure for an experimental engine, compared to K4s monthly average of 6,000 to 8,000 miles. This implied that the PRR had high regard for the S1's power and speed. The S1 helped PRR to handle the extreme busy wartime traffic until the end of WWII and paid off her high construction cost within one year. Crews liked the S1, partly because of its very smooth ride at speed. The great mass and inertia of the locomotive together with the unique, massive 6-wheel trailing truck soaked up the bumps and the surging often experienced with duplex locomotives. Operating performance and alleged speed records In terms of tractive effort and drawbar horsepower, the PRR S1 was the most potent reciprocating steam locomotive ever built for passenger service. Starting tractive effort calculated in the usual way (85% mean effective pressure) comes out , but the engine used 70.6% limited cutoff (presumably to increase port openings at