The
Pennsylvania Railroad
The Pennsylvania Railroad (reporting mark PRR), legal name The Pennsylvania Railroad Company also known as the "Pennsy", was an American Class I railroad that was established in 1846 and headquartered in Philadelphia, Pennsylvania. It was named ...
's S2 class was a
steam turbine locomotive
A steam turbine locomotive is a steam locomotive which transmits steam power to the wheels via a steam turbine. Numerous attempts at this type of locomotive were made, mostly without success. In the 1930s this type of locomotive was seen as a way ...
designed and built in a collaborative effort by
Baldwin Locomotive Works
The Baldwin Locomotive Works (BLW) was an American manufacturer of railroad locomotives from 1825 to 1951. Originally located in Philadelphia, it moved to nearby Eddystone, Pennsylvania, in the early 20th century. The company was for decades t ...
and
Westinghouse Electric & Manufacturing Company
The Westinghouse Electric Corporation was an American manufacturing company founded in 1886 by George Westinghouse. It was originally named "Westinghouse Electric & Manufacturing Company" and was renamed "Westinghouse Electric Corporation" in ...
, as an attempt to prolong the dominance of the steam locomotive by adapting technology that had been widely accepted in the marine industry. One was built, #6200, delivered in September 1944. The S2 was the sole example of the
6-8-6
Under the Whyte notation for the classification of steam locomotives by wheel arrangement, represents the arrangement of six unpowered leading wheels arranged into a three-axle leading truck, eight powered driving wheels, and six unpowered trail ...
wheel arrangement
In rail transport, a wheel arrangement or wheel configuration is a system of classifying the way in which wheels are distributed under a locomotive. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and c ...
in the
Whyte notation
Whyte notation is a classification method for steam locomotives, and some internal combustion locomotives and electric locomotives, by wheel arrangement. It was devised by Frederick Methvan Whyte, and came into use in the early twentieth ce ...
, with a six-wheel
leading truck
The leading wheel or leading axle or pilot wheel of a steam locomotive is an unpowered wheel or axle located in front of the driving wheels. The axle or axles of the leading wheels are normally located on a leading truck. Leading wheels are used ...
, eight
driving wheel
On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons (or turbine, in the case of a steam turbine locomotive). On a conventional, non-articulated locomotive, the driving wheels are all coupled ...
s, and a six-wheel
trailing truck
On a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle ( wheelset) located behind the driving wheels. The axle of the trailing wheels is usually located in a trailing truck. On some large locomotives, ...
. The S2 used a direct-drive
steam turbine
A steam turbine is a machine that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Parsons in 1884. Fabrication of a modern steam turbin ...
provided by the
Westinghouse Electric & Manufacturing Company
The Westinghouse Electric Corporation was an American manufacturing company founded in 1886 by George Westinghouse. It was originally named "Westinghouse Electric & Manufacturing Company" and was renamed "Westinghouse Electric Corporation" in ...
, geared to the center pair of axles with the outer two axles connected by
side rod
A coupling rod or side rod connects the driving wheels of a locomotive. Steam locomotives in particular usually have them, but some diesel and electric locomotives, especially older ones and shunters, also have them. The coupling rods transfer t ...
s; the fixed gear ratio was 18.5:1. Such design was to prevent energy loss and S2 achieved a mechanical efficiency of 97% which means only 3% of steam energy was lost within the propulsion equipment. The disadvantage of direct-drive steam turbine was that the turbine could not operate at optimal speeds over the locomotive's entire speed range. The S2 was the largest, heaviest and fastest direct-drive turbine locomotive design ever built.
Design specification
![PRR S2 Forward and Backward Turbine](https://upload.wikimedia.org/wikipedia/commons/f/fe/PRR_S2_Forward_and_Backward_Turbine.jpg)
The locomotive was to be a
4-8-4
Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of four leading wheels on two axles, eight powered and coupled driving wheels on four axles and four trailing wheels on two axles. The type w ...
, but wartime restrictions on light steel alloys increased weight until six-wheel leading and trailing trucks were needed; its construction was also delayed by
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
. Construction of the locomotive took place at the Baldwin plant in Eddystone. Two turbines were fitted, one for forward travel and a smaller one for reversing at speeds up to . Compressed steam at a rate of about 2,000 miles per hour was injected onto the turbine blades through 4 nozzles; thousands of turbine blades transmitted steam energy to the transmission gear. The maximum rotation speed of the forward turbine is 9,000 rpm, developing 6,900 hp; the reverse turbine generates 1,500 hp at 8,300 rpm. A monitoring system ensured that the forward turbine could only be started when the reverse turbine was switched off. Weight of propulsion equipment was 39,000 lbs., or 5.65 lbs/hp. A large boiler with a
Belpaire firebox
The Belpaire firebox is a type of firebox used on steam locomotives. It was invented by Alfred Belpaire of Belgium in 1864. Today it generally refers to the shape of the outer shell of the firebox which is approximately flat at the top and squa ...
and long
combustion chamber
A combustion chamber is part of an internal combustion engine in which the fuel/air mix is burned. For steam engines, the term has also been used for an extension of the firebox which is used to allow a more complete combustion process.
Interna ...
was fitted. An automatic lubrication system was installed, connecting the transmission case, where the driving gear wheels were immersed in a lubricant reservoir filled with lubricating oil. Lubricant goes through all lubrication points, including roller bearings on all axles via the filtered pipes with the help of two steam pumps. A
Worthington
Worthington may refer to:
People
* Worthington (surname)
* Worthington family, a British noble family
Businesses
* Worthington Brewery, also known as Worthington's
* Worthington Corporation, founded as a pump manufacturer in 1845, later a dive ...
-pattern
feedwater heater
A feedwater heater is a power plant component used to pre-heat water delivered to a steam generating boiler. Preheating the feedwater reduces the irreversibilities involved in steam generation and therefore improves the thermodynamic efficiency of ...
was fitted for increased efficiency. Twin air pumps for train braking were fitted below the running boards beside the smokebox front, and a large radiator assembly at the nose cooled the compressed air.
The turbine exhaust was piped through a set of four nozzles in the
smokebox
A smokebox is one of the major basic parts of a steam locomotive exhaust system. Smoke and hot gases pass from the firebox through tubes where they pass heat to the surrounding water in the boiler. The smoke then enters the smokebox, and is e ...
, providing an even draft for the fire and exiting through a unique quadruple stack. S2 had no
smoke deflector
Smoke deflectors, sometimes called "blinkers" in the UK because of their strong resemblance to the blinkers used on horses, and "elephant ears" in US railway slang, are vertical plates attached to each side of the smokebox at the front of a ste ...
when it was delivered from Baldwin to PRR in September 1944, but, soon after it began its service, PRR found out that the locomotive blew heavy smoke at lower speed during operation. So, a pair of small smoke deflectors was acquired and a thin semi-circular metal plate for smoke lifting was filled a few feet behind the smokestack. Apparently, these weren't adequate, so a much-larger pair which look like the "elephant ears" used on
New York Central
The New York Central Railroad was a railroad primarily operating in the Great Lakes and Mid-Atlantic regions of the United States. The railroad primarily connected greater New York and Boston in the east with Chicago and St. Louis in the Midw ...
class S1b 4-8-4
Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of four leading wheels on two axles, eight powered and coupled driving wheels on four axles and four trailing wheels on two axles. The type w ...
Niagara and
Union Pacific
The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Paci ...
FEF-3 4-8-4 was added at
Altoona Works
Altoona Works (also known as Altoona Terminal) is a large railroad industrial complex in Altoona, Pennsylvania. It was built between 1850 and 1925 by the Pennsylvania Railroad (PRR), to supply the railroad with locomotives, railroad cars and relat ...
in December, 1946. Using a smoke deflector was never a tradition of the
Pennsylvania Railroad
The Pennsylvania Railroad (reporting mark PRR), legal name The Pennsylvania Railroad Company also known as the "Pennsy", was an American Class I railroad that was established in 1846 and headquartered in Philadelphia, Pennsylvania. It was named ...
. Prior to S2 #6200, there were only three
K4s
The Pennsylvania Railroad (PRR) K4 4-6-2 "Pacific" (425 built 1914–1928, PRR Altoona, Baldwin) was its premier passenger-hauling steam locomotive from 1914 through the end of steam on the PRR in 1957.
Attempts were made to replace the ...
-installed smoke deflectors between 1939 and 1941, for an experimental purpose: PRR #5038, #3876 and #3878. Their smoke deflectors were all removed after the war, so the steam turbine #6200 was the only Pennsy locomotive with huge "elephant ears" after the war.
The tender of the PRR S2 #6200 was originally made for a class L1s locomotive with the designation 180-F-82. Later, it was assigned as 180-P-75 for class K4s No. 3768; the tender was rebuilt again and received the designation 180-P-85 for S2 6200 use. This large 16-wheel tender was similar to that used on the PRR's other large passenger locomotives, the
T1 and
S1. In order to reduce the crew's workload, a "Fluid Pressure Control System" () designed by Westinghouse engineer Harry C. May was installed on the locomotive. It controlled starting, running, reversing, power output, and speed, and limited speed in both directions of operation, all in one single control lever which was installed in front of the engineer's seat.
The locomotive proved to be powerful and capable, with reserves of power at speed and reasonable fuel economy. The turbine drive was easy on the track and allowed more power at the rail. During a test run officially arranged by PRR on 30 March 1945, S2 #6200 towing a
dynamometer car
A dynamometer car is a railroad maintenance of way car used for measuring various aspects of a locomotive's performance. Measurements include tractive effort (pulling force), power, top speed, etc.
History
The first dynamometer car was probably ...
was able to pull a 17-car train over a distance of 48 kilometers (level track) at a speed of between
Fort Wayne
Fort Wayne is a city in and the county seat of Allen County, Indiana, United States. Located in northeastern Indiana, the city is west of the Ohio border and south of the Michigan border. The city's population was 263,886 as of the 2020 Censu ...
and Chicago. Engineer Mr. Flaya Cartwright and Fireman Mr. M.E. Brown were assigned to this official test run. E.S. Cox, a British locomotive engineer, once traveled on the footplate and reported that "100mph was maintained and exceeded for 12 consecutive minutes". While economical at speed, the locomotive was highly-uneconomical at lower speed. The turbine used less steam than conventional locomotives above , but below that the locomotive used too much steam and fuel. The boiler normally operated at , but at low speed the pressure could drop as low as . The increased fuel usage at low speeds caused the firebox to run hotter, which sometimes caused stay bolts to break.
The locomotive's problems, the rapid decline of PRR's ridership since 1947 and the advantages of the emerging
diesel locomotive
A diesel locomotive is a type of railway locomotive in which the prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conveyed to the driving whee ...
ensured that #6200 would never be duplicated, but S2 still participated in the 1948
Chicago Railroad Fair
The Chicago Railroad Fair was an event organized to celebrate and commemorate 100 years of railroad history west of Chicago, Illinois. It was held in Chicago in 1948 and 1949 along the shore of Lake Michigan and is often referred to as "the last ...
with a T1 4-4-4-4 Duplex Steam Locomotive.
[Nation Railway Bulletin Vol.63 Number 1 , 1993] In August 1949, the locomotive suffered severe turbine damage. Since the maintenance costs rose steadily, the S2 was finally stored in
Crestline and
Altoona. In 1952, she was finally retired and was scrapped the following year.
Service history
The S2 was assigned to the Fort Wayne Division and based at the Crestline enginehouse. It hauled various prestigious passenger trains serving the New York to Chicago corridor such as
The Broadway Limited
The ''Broadway Limited'' was a passenger train operated by the Pennsylvania Railroad (PRR) between New York City and Chicago. It operated from 1912 to 1995. It was the Pennsylvania's premier train, competing directly with the New York Central Ra ...
, The
Liberty Limited
The ''Liberty Limited'' was a named train on the Pennsylvania Railroad. It ran from Washington D.C. to Chicago, Illinois, through Baltimore, Harrisburg and Pittsburgh. It began running on September 27, 1925, as a replacement for the '' Washingt ...
,
The Trail Blazer, The
General
A general officer is an Officer (armed forces), officer of highest military ranks, high rank in the army, armies, and in some nations' air forces, space forces, and marines or naval infantry.
In some usages the term "general officer" refers t ...
, The
Manhattan Limited
The ''Manhattan Limited'' was a passenger train of the Pennsylvania Railroad which served the Chicago—New York City route.
History
The ''Manhattan Limited'' was originally the ''Seashore Limited'', an eastbound-only train which was rena ...
and The Golden Arrow on the route between Chicago and
Crestline, Ohio
Crestline is a village in Crawford and Richland Counties in the U.S. state of Ohio. Crestline's population was 4,630 at the 2010 census. It is the third largest municipality in Crawford County. The Crawford County portion of Crestline is part ...
(283 miles/ 446 km). S2 also hauled troop trains and was seen towing express freight trains. PRR S2 #6200, as an experimental prototype of a direct-drive steam turbine locomotive, ran 103,000 miles in total before it was completely withdrawn from service in August, 1949 and would soon await the scrapper's torch. The 6200 was eventually scrapped in Conway, Pennsylvania.
In popular culture
The model train company
Lionel made several models of the S2. The first ones, 671 and 2020, were released in 1946 and were discontinued in 1949. The 681 turbine's first production run was in 1950 and 1951. It was similar to both of the original turbine models but the 681 has Lionel's Magne-Traction feature which makes the wheels magnetic. In 1952, The Korean War caused a shortage of magnetic material, so the 671 was reissued as the 671rr (671 rerun). The 681 returned the next year. In 1954 and 1955, another turbine, numbered 682, was released. The 682 was basically a 681 but with valve gear on the wheels and a white stripe painted on both sides.
References
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External links
The Duplex and Experimental Steam Engines of the PRRPennsylvania Railroad S2 steam turbine*
ttp://www.prrths.com/estore/keystone_magazine.html#2012 "The Keystone" Magazine - Autumn 2012 Volume 45 - Number 3 - The S2 Turbine 686S2 6-8-6 Steam Turbine (2014, in Russian) Pennsylvania Railroad patent drawings (January 20, 2012 ''Classic Trains'' Magazine) *
{{PRR locomotives
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Baldwin locomotives
6-8-6 locomotives
Steam locomotives of the United States
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Individual locomotives of the United States
Experimental locomotives
Scrapped locomotives
Unique locomotives
Passenger locomotives
Standard gauge locomotives of the United States