PRR class T1

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PRR class T1
PRR class T1
PRR class T1
Numbering: PRR 5500-5549
PRR 6110-6111
Number: 52
Manufacturer: Baldwin
Year of construction (s): 1942-1946
Type : 2'BB2 'h4
Gauge : 1435 mm ( standard gauge )
Length over buffers: 37,433 mm
Service mass: 227.8 t
Top speed: 193 km / h
Indexed performance : over 6000 hp
Driving wheel diameter: 2032 mm
Impeller diameter front: 914 mm
Rear wheel diameter: 1067 mm
Cylinder diameter: 483 mm
Piston stroke: 660 mm
Grate area: 8.55 m²
Superheater area : 156.00 m²
Evaporation heating surface: 391.80 m²
Water supply: 73.8 m³
Fuel supply: 37.2 tons of coal
PRR class T1 1943

The class T1 of the Pennsylvania Railroad were streamlined steam locomotives for heavy express trains . They were designed as duplex locomotives with the wheel arrangement 2'BB2 ', with four driven axles and four cylinders. The locomotives manufactured between 1942 and 1946 were among the largest, most powerful and fastest steam locomotives ever built in the world.

construction

Overall structure and drive

The locomotives were over 37 meters long and had a service weight of over 227 tons. The locomotives were coupled with eight-axle tenders . The tenders were equipped with a water scoop. They held 73.8 m³ of water and 37.2 t of coal. The streamlined fairing was designed by Raymond Loewy . The T1 class was powered by two two- cylinder engines , which were arranged one behind the other in a common frame. The two cylinders of the front engine drove the first and second, and the two cylinders of the rear engine drove the third and fourth coupled axles . As a result, the piston forces on the trunnions were lower than in steam locomotives with the same number of coupled axles, but only one engine. Since it is not possible to completely balance the reciprocating masses of a two-cylinder engine, another advantage was the reduction of the “hammer-blow effect”. Disadvantages of this design were the tendency to skid when starting, a larger fixed wheelbase and, due to the multi-part design, a greater maintenance effort.

control

After good experience with a converted K4s, the class T1 locomotives were equipped with a Franklin valve control. However, this control turned out to be less reliable in series production than the usual Heusinger control . The locomotive with the number 5547 was then converted to normal piston valves and designated as T1a. Another locomotive, number 5500, received a Franklin type B valve control.

Performance data

Extensive tests in the workshops in Altoona in August 1944 showed an output on the wheel circumference of 6080  hp at almost 140  km / h , which at this speed corresponded to the output of three K4s class locomotives. In practice, the locomotives could move a train with 16 cars and a mass of 1020 t between Fort Wayne and Chicago at an average speed of 164 km / h. The T1 6111 was the only one to have a booster , an auxiliary steam engine with which particularly heavy trains can be started more easily.

Development history

After the PRR had behaved quite conservatively in steam locomotive construction until the 1930s, it switched to electrifying many of its lines. Class K4s locomotives from the years 1914 to 1928 were usually used for steam-hauled express trains , which, due to the ever increasing train loads, were often dependent on cost-intensive leader . As a consequence and in order to keep up with the more powerful steam locomotives of the competing New York Central , which had already procured locomotives with the 2'C2 'and later 2'D2' wheel arrangements in the 1930s, the PRR changed its procurement policy, which had been conservative up to that point. In the railway's own workshops in Altoona , the PRR built a duplex locomotive with a 3'BB3 'h4 wheel arrangement, class S1 . The construction proved to be suitable in principle, but the individual piece was oversized and did not prove itself in everyday use.

Operational use

Since the S1 class had proven to be too oversized and not suitable for everyday use, Baldwin delivered two preliminary samples of the T1 class in 1942, the numbers 6110 and 6111. After the everyday suitability and the end of the war - only freight locomotives were allowed to be built during the war from November 1945 to August 1946 another 50 locomotives were built by Baldwin and the Juniata workshops of the PRR with a slightly different design. They received the numbers 5500 to 5549. The 5524, delivered on June 14, 1946, was the last steam locomotive from the railway's own workshops in Altoona , while the 5546, delivered by Baldwin on August 27, 1946, was the last steam locomotive that the PRR ever procured.

After the PRR recorded a deficit for the first time in its history in 1946 and the competing New York Central doubled its top trains, the PRR decided without further ado to catch up. Since the highest quality trains, for which the T1 class was intended, were first dieselized for advertising reasons, these machines were actually no longer needed. Some locomotives, some almost brand new, were loaned to two railway companies for test drives. However, this did not result in a sale, as these railways had different requirements for the locomotives. The T1 locomotives were therefore used on the PRR network for a few years. None of the locomotives have survived, but there is a steam-powered model based on original plans on a 1: 8 scale.

Until the early 1950s, the T1 locomotives were used in express train service between Harrisburg , Altoona, Pittsburgh , Chicago and St. Louis . They had no problems on the level with heavy express trains reaching the scheduled speed of 120 mph (193 km / h). According to information from employees, trains with class T1 and S1 locomotives are said to have reached speeds of over 200 km / h. Since neither the T1 nor the S1 were deployed in front of the measuring vehicle, there are no officially confirmed data on the maximum speed. The machines were reliable provided they were carefully maintained. The inaccessible seat of the valve controls and the otherwise very conservative PRR locomotive designs led to the neglect of the T1 locomotives in everyday operation with corresponding consequences for operational readiness.

New construction of a T1

The US non-profit organization Pennsylvania Railroad T1 Steam Locomotive Trust has set itself the goal of rebuilding a T1 according to the original plans, if these are still available. The T1 Trust estimates the cost of the project to 10 million US dollars and is based on a completion in 2030. To date (as of 2019) the driver's cab, the front part of the cladding, parts of the boiler and some drive wheels have been completed. The Western New York Railway Historical Society acquired a historic tender that was used behind a PRR class M1 in earlier times. The well-preserved tender is identical to the former class T1 tenders except for the streamlined cladding and is being refurbished. The locomotive with the designation Pennsylvania Railroad 5550 is to be used on main lines for special trips. Another goal is to break the world speed record for steam locomotives . The fastest steam locomotives to this day are the German 05 002 and the British Mallard of the LNER class A4 , which were proven to have reached speeds of just over 200 km / h in the 1930s  . The official record is held by the Mallard , which reached 201.2 km / h on July 3, 1938. The Trust's engineers estimate that the new T1 will reach speeds of up to 225 km / h (140  mph ).

literature

  • Wilhelm Reuter: record locomotives . Motorbuch Verlag, Stuttgart, ISBN 3-87943-582-0 .
  • Alvin Staufer: Pennsy Power . Staufer, 1962.
  • Brian Reed: Loco Profile 24: Pennsylvania Duplexii . 1972.
  • Stefan Vockrodt: The most beautiful beast. A tribute to the Pennsylvania Railroad T1 . In: Bahnepoche, No. 24, autumn 2017, pp. 40–48.

Web links

Individual evidence

  1. ↑ The world's fastest steam loco? Retrieved December 20, 2017.
  2. ^ The T1 Trust. Retrieved December 18, 2017 .