The PRR S1 class steam locomotive (nicknamed "The Big Engine") was a single experimental duplex locomotive of the Pennsylvania Railroad. It was designed to demonstrate the advantages of duplex drives espoused by Baldwin Chief Engineer Ralph P. Johnson. [1]

Nov 17, 2020 · Nicknamed "The Big Engine," the S1 was the longest reciprocating steam locomotive ever (just over 140 ft); it was too big for many PRR curves. Along with wheel slippage, this limited the S1's usefulness.

Jul 5, 2018 · The S1 was designed to haul a 1,200-ton (1,089-t) passenger train at 100 mph (161 km/h). The engine developed around 6,500 indicated hp (4,847 kW) at 100 mph (161 km/h) and had a maximum tractive effort of some 76,400 lbf (339.8 kN) based on an 85% efficiency factor.

Sooty and dark in its neglect, the locomotive came to life as it hustled unnamed No. 43's 15-car train (all heavyweights) over 27 miles (43.5 km) of dead-straight track at an average speed of 97 mph (156 kph).

Dec 24, 2023 · This O scale model of the S1 was built from plans submitted to Ed Alexander whilst the 12" to the foot model was being built . Both model and real engine were on display at the 1939 NYC World Fair lettered " American Railroads" .

Sep 23, 2018 · Starting from a design directive that called for a duplex engine capable of hauling a 1,000-ton passenger train 100 MPH on a level grade, PRR contracted with three of the largest suppliers of steam engines to build the S-1 at PRR’s sprawling Juniata Works at Altoona, Pennsylvania (also considered one of the largest locomotive and rail car ...

The first experimental duplex on the PRR was the S1, a huge rigid frame duplex locomotive of the 6-4-4-6 wheel arrangement. This engine was over 146' long! This locomotive was built by the PRR at Altoona in 1939; it was hailed as the largest locomotive ever built.

The Pennsylvania Railroad 's class S1 comprised a single steam locomotive of 6-4-4-6 wheel arrangement in the Whyte notation, the only locomotive of such arrangement ever constructed.

Sep 3, 2010 · The PRR S1 class steam locomotive (nicknamed "The Big Engine") was an experimental locomotive that was the largest rigid frame passenger locomotive ever built. The streamlined Art Deco styled shell of the locomotive was designed by Raymond Loewy.

Few locomotives made a public debut and statement like the Pennsylvania's "Big Engine" - the S1. Unveiled at the 1939 World's Fair The 140 foot long streamlined behemoth shocked the imagination with its promise of speed, power and bright futures.