Gas turbine–electric locomotive

For gas turbine locomotives with mechanical transmission, see Gas turbine locomotive.

UP 18, preserved at the Illinois Railway Museum.

A gas turbine-electric locomotive, or GTEL, is a locomotive that uses a gas turbine to drive an electric generator or alternator. The electric current thus produced is used to power traction motors. This type of locomotive was first experimented with in 1938 but reached its peak in the 1950s to 1960s. Few locomotives use this system today, although there has been some level of interest by Bombardier Transportation.

Description

In a GTEL a turbine engine, similar to a turboshaft engine, drives an output shaft that is in turn attached to an electrical generator via a system of gears. The electrical power is distributed to power the traction motors that drive the locomotive. In overall terms the system is very similar to a conventional diesel-electric, with the large diesel engine replaced with a smaller gas turbine of similar power.

A gas turbine offers some advantages over a piston engine. There are few moving parts, decreasing the need for lubrication and potentially reducing maintenance costs, and the power-to-weight ratio is much higher. A turbine of a given power output is also physically smaller than an equally powerful piston engine, allowing a locomotive to be very powerful without being inordinately large. However, a turbine's power output and efficiency both drop dramatically with rotational speed, unlike a piston engine, which has a comparatively flat power curve. This makes GTEL systems useful primarily for long-distance high-speed runs.

Union Pacific operated the largest fleet of such locomotives of any railroad in the world, and was the only railroad to use them for hauling freight. Most other GTELs have been built for small passenger trains, and only a few have seen any real success in that role. After the oil crisis in the 1970s and the subsequent rise in fuel costs, gas turbine locomotives became uneconomical to operate, and many were taken out of service. Additionally, Union Pacific's locomotives required more maintenance than originally anticipated, due to fouling of the turbine blades by the Bunker C oil used as fuel. This type of locomotive is now rare.

History

SNCF's turbotrain in Houlgate on the Deauville-Dives railway line in summer 1989.

Switzerland

Swiss Federal Railways agreed to test a gas turbine-electric locomotive Am 4/6 in 1939 and it was delivered in 1941/42. It was built by Brown Boveri with the unusual wheel arrangement of 1A-Bo-A1 and had a 2,200 horsepower (1.6 MW) turbine. This is one of the first applications of gas turbine technology of any sort; jet engines in England and Germany were first being started at about this time and would not enter squadron use until 1944.

United Kingdom

The Great Western Railway ordered two gas turbine-electric locomotives in the 1940s but these were not delivered until after nationalisation. They were numbered 18000 and 18100 by British Railways. Number 18000 was built in Switzerland with a Brown Boveri industrial gas turbine of 2,500 horsepower (1.9 MW). In contrast, number 18100 was built in Britain by Metropolitan Vickers and had an aircraft-type gas turbine of 3,000 horsepower (2.2 MW). Maximum speed, in both cases, was 90 miles per hour (145 km/h).

The British Rail APT-E, prototype of the failed Advanced Passenger Train, was turbine-powered. Like the French TGV, later models were electric instead. This choice was made because British Leyland, the turbine supplier, ceased production of the model used in the APT-E.

France

SNCF (French National Railways) used a number of gas-turbine trainsets, called the Turbotrain, in non-electrified territory. These typically consisted of a power car at each end with three cars between them. Turbotrain was in use up until 2005.

The first TGV prototype, TGV 001, was also powered by a gas turbine, but steep oil prices prompted the change to overhead electric lines for power delivery.

United States

Further information: [[:Union Pacific GTELs]], [[:UAC TurboTrain]], and [[:Turboliner]]

Union Pacific ran a large fleet of turbine-powered freight locomotives starting in the 1950s. These were widely used on long-haul routes, and were cost-effective despite their poor fuel economy due to their use of "leftover" fuels from the petroleum industry. At their height the railroad estimated that they powered about 10% of Union Pacific's freight trains, a much wider use than any other example of this class. As other uses were found for these heavier petroleum byproducts, notably for plastics, the units became too expensive to operate and they were retired from service by 1969.

In 1950, Westinghouse built an experimental 4000 HP turbine locomotive, #4000, known as the Blue Goose, with a B-B-B-B wheel arrangement. While it was demonstrated succesfully in both freight and passenger service, no production orders followed, and it was scrapped in 1952.

In the 1960s United Aircraft built the Turbo passenger train, which was tested by the Pennsylvania Railroad and later used by Amtrak and VIA Rail. VIA's remained in service into the 1980s and had an excellent maintenance record during this period, but were eventually replaced by the LRC in 1982.

Amtrak purchased two different types of turbine-powered trainsets, which were both called Turboliners. The first set were similar in appearance to SNCF's Turbotrain, though compliance with FRA safety regulations made them heavier and slower than the French trains. None of the first set of Turboliners remain in service. Amtrak also added a number of similarly named Rohr Turboliners (or RTL) to its roster. There were plans to rebuild these as RTL IIIs, but the program has been cancelled and the units are being sold or scrapped.

Canada

Canadian National Railways (CN) was one of the operators of the Turbo, which were passed on to VIA Rail. They operated on the major Toronto-Montreal route between 1968 and 1982, when they were replaced by the LRC.

In 2002, Bombardier Transportation announced the launch of the JetTrain, a high-speed trainset consisting of tilting carriages and a locomotive powered by a Pratt & Whitney turboshaft engine. No JetTrains have yet been sold for actual service.

Russia

In 1959 the G1-01 freigh GTEL was introduced. This was the firs russian (soviet) gas turbine locomotive. It was intended to be double-section with 12 axles and a turbine engine at each section, yet only one of the sections was built. It went testing and by the early 1970s the programme was ended. The turbine (the only one installed) has maximum power of 3500 hp (2611 kW) of which 2030 hp (1514 kW) are available at the wheels. The locomotive's maximum speed is 100 km/h (62 mph). It has C-C wheel arrangement with wheel diameter of 1050 mm (41.3 in). The locomotive's service weight is 141 metric tons. It has 17:75 gear ratio. For moving the locomotive itself and other auxiliary work, a diesel engine is placed on board, with power increased to 300 hp after some improvements in 1965. Also on board is located a ventilation system and a cooling system for the oil of the turbine and diesel engines and for the water of the diesel engine. A tank between the axles contains 9.5 metric tons of heavy fuel, the main fuel of the locomotive. About 1760 liters (465 U.S. gallons) of diesel fuel, for the auxiliary diesl, is placed on board. The G1-01 has continuous tractive effort of 230.5 kN (51,809 lbf) at 23.3 km/h (14.5 mph).

In 1964 GP1 was built. This was a passinger GTEL, with a cab at each end. Only two units were made, which were used also in regular service. The turbine's maximum output is 3500 hp (2611 kW) of which 2310 hp (1723 kW) are available at the wheels. The locomotive's service weight is 128.4 metric tons. It's maximum speed is 160 km/h (99.5 mph), with tractive effort of 3.9 kN (8,819 lbf). It has C-C wheel arrangement and 39:185 gear ratio. An auxiliary diesel engine with 400 hp is used on board. Again, ventilation and cooling systems for the turbine and diesel engines are placed on board. The GP1 has continuous tractive effort of 122.6 kN (27,558 lbf) at 50 km/h (31 mph). The locomotive stores on board 12.5 metric tons of heavy fuel and about 1170 liters (309 U.S. gallon) of diesel fuel.

In 2006 GEM-10, a switcher GTEL was introduced. It runs on liquefied natural gas. The turbine's maximum power output is 1000 kW (1340 hp). The GEM-10 has a C-C wheel arrangement.

In 2007 TGEM10-0001, another switcher GTEL was introduced. It consists of two units, a cow-calf setup. The TGEM10 runs on liquefied natural gas with fuel capacity of about 3 metric tons, located in the cabless unit, sufficient for about 7 days of average workload. The cabless unit also carries one half of the ultra-high energy capacitors. The locomotive has a B-B+B-B wheel arrangement. The turbine, located in the cab unit, has maximum power of 1000 kW (1340 hp). The other half of the ultra-high energy capacitors, the compressors, the torque converters and the ventilation system are all located in the cab unit . The ultra-high energy capacitors are used for starting the turbine engine and for partial regeneration of the brakes. They also increase the tractive current for the acceleration of the train and to smooth out sudden load changes on the turbine engine. The continuous tractive effort is 480 kN (107,908 lbf) at 6 km/h (3.7 mph). During heavy shunting service, all 8 traction motors are used. At speeds above 15 km/h (9.3 mph), the TGEM10 uses only the 4 traction motors on the cab unit. The locomotive's maximum speed is 100 km/h (62 mph). Its service weight is 172 metric tons. The locomotive wheels are 1050 mm (41.3 in) in diameter. The TGEM10 can work with trains weighing over 6000 metric tons.

In 2007 the GT1-001 freight GTEL was ready and began test runs operated by the Russian Railways. The turbine's maximum power output is 8300 kW (11126 hp). The locomotive runs on liquefied natural gas with fuel capacity of 17 metric tons, sufficient for up to 1000 km (620 mi) without refueling. It's planned to be used in Siberia and to pull trains weighing over 12000 metric tons. The maximum speed of the locomotive is 100 km/h (62 mph). The locomotive's service weight is 300 metric tons. The gas turbine engine, the main and auxiliary generators and other parts of the auxiliary system (control stand, ventilation for the electrical equipment, brake compressor and system for preparing the gas) are located in one of the locomotive's sections while the other contains the fuel and the auxiliary diesel-generator plus additional ventilation and control stand. The maximum power output of the main generator is 7370 kW and the auxiliary's maximum output is 600 kW. The auxiliary diesel-generator is used for moving the locomotive itself, getting the locomotive's systems in working conditions and starting the turbine engine, after which it's turned off. The GT1 has an hourly tractive effort of 677 kN (152,119 lbf) at 31.1 km/h (19.3 mph) and continuous tractive effort of 618 kN (138,891 lbf) at 47 km/h (29.2 mph). The locomotive has 12 axles, 6 under each section. All axles are powered and arranged in pairs, giving a B-B-B+B-B-B wheel arrangement. Up to three GT1 locomotives can be coupled.

External links

• Photos of Union Pacific turbine locomotives, including the ill-fated no. 80
• British Railways 18000
• Swiss gas turbine-electric locomotive

References

• Historical UP locomotives: Gas turbine locomotives
• Gas Turbine locomotive FAQ
• Gas turbines FAQ - NE Rails
• Union Pacific story 1934-1982 part 3
• Locomotive Engineers Journal; July, 1949