The reference for locomotives and railcars
Pennsylvania class S2
United States | 1944 | only one produced
No. 6200 in March 1944
No. 6200 in March 1944
Mike Robbins

The S2 was the largest steam locomotive ever with direct axle drive from a turbine. Delivered by Baldwin and Westinghouse in 1944, it was used by the PRR primarily in front of important express trains. Because the turbine was located directly between the second and third coupled axle and drove it via gears, there were only small mechanical losses. With an output of 6,900 hp, it was able to sustain over 100 mph, but the steam consumption of the turbine at low speeds was higher than that of conventional steam locomotives. In connection with the complicated maintenance, this initially led to the decommissioning in 1949 and the subsequent scrapping.

ManufacturerBaldwin, Westinghouse
Axle config6-8-6 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length122 ft 7 1/4 in
Total wheelbase108 ft
Empty weight537,000 lbs
Service weight589,920 lbs
Adhesive weight271,450 lbs
Total weight1,032,100 lbs
Axle load72,300 lbs
Water capacity19,500 us gal
Power sourcesteam turbine
Top speed110 mph
Engine output6,900 hp (5,145 kW)
Power Plant
Driver diameter68 in
Boiler pressure310 psi
Grate area120 sq ft
Firebox area607 sq ft
Tube heating area3,588 sq ft
Evaporative heating area4,195 sq ft
Superheater area2,050 sq ft
Total heating area6,245 sq ft
Calculated Values
steam locomotive
last changed: 03/2023

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