PRR class S2
| PRR class S2 | |
|---|---|
 PRR class S2 No. 6200
|
|
| Numbering: | No. 6200 |
| Number: | 1 |
| Manufacturer: | Baldwin |
| Year of construction (s): | 1944 |
| Retirement: | 1952 |
| Axis formula : | 3'D3 ' |
| Gauge : | 1435 mm ( standard gauge ) |
| Length over coupling: | 37,370 mm |
| Fixed wheelbase: | 5943 mm |
| Total wheelbase: | 16,154 mm |
| Wheelbase with tender: | 32,880 mm |
| Empty mass: | 243.5 t |
| Service mass: | 267.9 t |
| Friction mass: | 123.2 t |
| Wheel set mass : | 29.5 t - 32.8 t |
| Top speed: | 160 km / h |
| Installed capacity: | 5075 kW (6900 hp) |
| Starting tractive effort: | 340 kN |
| Driving wheel diameter: | 1727.2 mm |
| Impeller diameter front: | 914.4 mm |
| Inner impeller diameter: | 1066.8 mm |
| Boiler overpressure: | 21.8 bar |
| Grate area: | 10.75 m² |
| Radiant heating surface: | 56.39 m² |
| Tubular heating surface: | 333.33 m² |
| Superheater area : | 183.94 m² |
| Evaporation heating surface: | 573.66 m² |
| Service weight of the tender: | 203.9 t |
| Water supply: | 73.8 m³ |
| Fuel supply: | 38.6 tons of coal |
| Power transmission: | mechanically |
The S2 of the Pennsylvania Railroad was the most powerful ever built steam locomotive . The locomotive with the road number 6200 was manufactured by Baldwin Locomotive Works in 1944 and scrapped again in 1953.
history
In the mid-1930s, the Pennsylvania Railroad became aware of the development of steam turbine locomotives. In particular, the success of locomotive No. 6202 on the London, Midland and Scottish Railway aroused their interest. The railway company's engineers therefore developed their own concept for a steam turbine locomotive with mechanical power transmission together with the turbine manufacturer Westinghouse Electric and Manufacturing Co. and Baldwin. The engineers promised a higher degree of efficiency and a lower overall weight than with electrical power transmission. The first plan was to convert an existing locomotive. Since the cost of this measure was almost the same as the cost of a new building, it was waived. The designs were completed in 1941. The United States' entry into World War II and the associated shortages of lightweight materials led to another redesign.
The locomotive was completed by the Baldwin Locomotive Works in September 1944. The tests took place on the route between Chicago and Crestline in front of freight and heavy express trains. The machine had excellent runnability and high draw hook performance.
A maximum output of 4568 kW (6206 hp) was determined on the test bench at 121 km / h. During test drives, the locomotive was able to pull a 17-car train over a distance of 48 kilometers at a speed of 169 km / h. At a speed of 106 km / h and an output of 3680 hp, the best overall efficiency was achieved with 7.7%. The pulling power of the locomotive exceeded all comparable steam and diesel locomotives (the latter at speeds over 64 km / h). The steam consumption was lower than with other steam locomotives at speeds over 48 km / h. When starting up and at low speeds, however, the steam consumption was significantly higher. So it happened that the boiler pressure could fall below 14 bar when starting up.
Due to this strongly changing boiler load, stud bolts were frequently broken .
In August 1949, the locomotive suffered severe turbine damage. As the maintenance costs rose steadily, the S2 was finally parked in Crestline and Altoona . In 1952 it was finally retired and scrapped the following year.
Constructive features
The design of the exhaust steam turbine locomotive S2 largely corresponded to a conventional steam locomotive . Instead of the piston steam engine, however, the steam turbine was arranged. The Belpaire boiler was provided with a combustion chamber and a mechanical grate feeder ( stoker ). The hourly coal consumption was around 2 tons. A Worthington type feed water preheater was installed.
The drive set, which was based on a turbine for ship propulsion, was arranged between the second and third coupling axles. The main turbine was on the right and a shunting turbine with 1500 hp for reversing on the left side of the locomotive. The shunting turbine was intended for speeds of up to 35 km / h and was switched on by means of a hydraulic clutch when the machine system was at a standstill. A monitoring system ensured that the main turbine could only be started when the shunting turbine was switched off.
The drive train was a self-contained system with a downstream gearbox. The turbine had a maximum speed of 9000 revolutions per minute. The power was transmitted to the second and third coupled axles via a Westinghouse spring drive . The gear ratio was 18.5: 1. The other driving axles were driven by coupling rods .
The steam was fed from the steam collecting box into the steam turbine via the four control valves. In the steam turbine, the steam pressure was reduced from 21.8 bar to 1.05 bar. This steam was then led into the chimney through four blowpipes.
The frame was a cast steel part. All axle and coupling rod bearings were designed as roller bearings. War-related restrictions on the use of light metal connections meant that three axles instead of two had to be arranged in the running wheel bogies. During a general inspection in 1947, the locomotive was fitted with smoke deflectors . Two air pumps for the braking system were located on either side of the smoke chamber. Below the smoke chamber on the front of the locomotive was a large cooler for the compressed air.
The locomotive's tender was originally made for a class I1 locomotive with the designation 180-F-82. Later it was assigned to Class K4s No. 3768 as the 180-P-75 . The tender was converted again for use with the No. 6200 and was given the designation 180-P-85. He had two bogies with four axles each.
literature
- Rolf Ostendorf: Steam Turbine Locomotives . The history of the development of a bygone special steam locomotive design. Franckh'sche Verlagshandlung, Stuttgart 1971, p. 59-61 .
- Rolf Ostendorf: Unusual steam locomotives from 1803 to today . A reflection of special constructions. 2nd Edition. Motorbuch Verlag, Stuttgart 1978, ISBN 3-87943-406-9 , p. 246 .
- Raimar Lehmann: Steam locomotive special designs . 2nd unchanged edition. VEB Verlag Technik, Berlin 1987, ISBN 3-341-00336-3 , p. 152 .
- George H. Drury: Guide to North American Steam Locomotives . 1st edition. Kalmbach Publishing Co., Waukesha, WI 1993, ISBN 0-89024-206-2 , pp. 394 .
- Pennsylvania's turbine engine . In: Trains . Kalmbach Publishing Co., January 1945, ISSN 0041-0934 , p. 14-15 .
- Driving Gear for Turbine Locomotives . In: Trains . Kalmbach Publishing Co., June 1945, ISSN 0041-0934 , p. 26-29 .
- Charles Kerr Jr .: The Steam Turbine: Coal's New Hope . In: Trains . Kalmbach Publishing Co., June 1947, ISSN 0041-0934 , p. 15-18 .
