   #copyright

Gas turbine-electric locomotive

2007 Schools Wikipedia Selection. Related subjects: Railway transport

   UP 18, preserved at the illinois Railway Museum.
   Enlarge
   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 1920 but reached its peak in
   the 1950s to 1960s. The turbine (similar to a turboshaft engine) drives
   an output shaft, which drives the alternator via a system of gears.
   Aside from the unusual prime mover, a GTEL is very similar to a
   diesel-electric. In fact, the turbines built by GE used many of the
   same parts as their diesels.

   A turbine offers some advantages over a piston engine. There are few
   moving parts, decreasing the need for lubrication and 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.
   Turbines also produce a great deal of noise.

   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. This type of locomotive is now rare.

Union Pacific's turbine fleet

   UP 50, the prototype gas turbine locomotive.
   Enlarge
   UP 50, the prototype gas turbine locomotive.

   Union Pacific has long sought the biggest and best locomotives
   available. In the 1930s a pair of steam turbine locomotives were tried
   out but ultimately rejected. Even before World War II Union Pacific had
   been adding diesels to its roster, but these were mostly for passenger
   trains. The idea of lashing together four diesels to equal the power of
   a single steam locomotive was unappealing, so the search began for
   something bigger. General Electric had been building gas turbines for
   aircraft and proposed using something similar to create a more powerful
   locomotive. Union Pacific had discovered that the maintenance costs for
   a locomotive were independent of the locomotive's power output. Using a
   smaller number of more powerful locomotives would thereby save money.

   Union Pacific decided that the best way for the turbine locomotives to
   realize their potential would be to put them on mainline freight
   trains. The long uninterrupted runs and relatively high speeds would
   keep the turbines turning at high speeds. The turbines were considered
   for use on the Los Angeles- Salt Lake City route, but their high noise
   levels resulted in them being banned from operating into Los Angeles.

   Union Pacific operated the largest fleet of turbine locomotives of any
   railroad in the world. The turbines were used extensively; at one point
   Union Pacific claimed that the turbines hauled more than 10% of the
   railroad's freight. Their fuel economy was rather poor, as the turbine
   consumed roughly twice as much fuel as an equally powerful diesel
   engine. This was initially not a problem, since Union Pacific's
   turbines were fueled by Bunker C heavy fuel oil. This highly viscous
   fuel was far less expensive than Diesel, but difficult to handle. When
   cold, its consistency was likened to tar or molasses. To solve this
   problem, a heating apparatus was built into the fuel tenders to heat
   the fuel to 200 °F (93 °C) before being fed into the turbine. Soot
   buildup and blade erosion caused by corrosive ashes plagued all of the
   turbines.
   UP 55, one of the first generation turbines.
   Enlarge
   UP 55, one of the first generation turbines.

   The turbines were delivered in three main groups after extensive
   testing of a prototype. Union Pacific intended to use the turbines to
   replace the famous Big Boys which were about to be retired at the time.

   1948
   After Union Pacific expressed interest, Alco-GE built a prototype, GE
   101. After tests in the Northeast, it was renumbered UP 50. Painted in
   Union Pacific Armour Yellow, UP 50 began an extensive round of tests.
   Union Pacific never took possession of this locomotive, however. This
   was one of the few internal combustion-powered locomotives used in
   North America that had a cab at each end. The cabs themselves resembled
   the FA units being built by Alco-GE at that time. The sides of the
   locomotive had numerous air intake louvers which could be opened and
   closed in varying patterns.

   It was a carbody unit with a B+B-B+B wheel arrangement. The turbine
   produced 4800 horsepower (3.6 MW), of which 4500 hp (3.4 MW) was
   available for traction. This power output was more than double that of
   diesel-electric locomotives of that era. A small diesel engine was also
   installed inside the unit. This was used for moving the unit around
   when uncoupled and for starting up the turbine. The turbine would first
   be spun up to starting speed, then combustion would be started using
   the onboard diesel fuel supply. Once the turbine was running, the fuel
   supply would automatically switch to the Bunker C fuel oil. This
   machine weighed 500,000 pounds (230,000 kg) and was over 80 feet (24 m)
   long.
   UP 68, one of the second generation "veranda" turbines.
   Enlarge
   UP 68, one of the second generation "veranda" turbines.

   1952
   Units 51 to 60 were delivered to the Union Pacific. These were
   essentially identical to the prototype except that they had cabs at
   only one end. These and later turbines were nearly always equipped with
   fuel tenders converted from old steam locomotive tenders, with a
   capacity of 23,000 US gallons (87,000 l). A heating apparatus was
   installed to make sure that the viscous fuel would flow properly. The
   tenders were also equipped with MU connections so that trailing diesel
   locomotives could be controlled as well. The turbines rarely operated
   alone; most usually operated with at least two diesel locomotives in
   their consist, as protection. Should the turbine fail en route, the
   diesels could be used in allowing the train to clear the main track.

   UP 57 was briefly converted to burn propane and was equipped with a
   pressurized tank car as a tender. This fuel burned cleanly but was more
   difficult to transport. No other conversions were attempted.

   1954
   Units 61 to 75 were delivered to the Union Pacific. These were visibly
   different from the previous generation because of the addition of
   external walkways on the sides of the locomotives, earning them the
   nickname "verandas" and making them hybrids of carbody and hood
   locomotives. The turbine and electrical equipment were essentially the
   same, though the variable side louvers were replaced by fixed ones.
   UP 26, one of the third generation turbines.
   Enlarge
   UP 26, one of the third generation turbines.

   1958-1961 Units 1 to 30 were delivered to the Union Pacific. These
   units, nicknamed "Big Blows" because of their high noise levels, were
   very different from the previous generations. A larger turbine produced
   8500 horsepower (6.3 MW), and the unit consisted of two permanently
   coupled six-axle units, giving a C-C+C-C wheel arrangement. The first
   unit contained the cab, auxiliary diesel engine, and other control
   equipment. The second unit contained the turbine and electric
   generators. Together, the locomotive looked like an A- B set, which was
   reinforced by the numbers assigned to the units. The two halves of no.
   19, for instance, would be numbered 19 and 19B. These turbines
   eventually displaced units 51 to 75 from service. There had also been
   problems with fuel filters clogging on the earlier turbines, so it was
   decided to filter the fuel before filling up the locomotive fuel tanks
   and the tender.

   Rumors persist that the Big Blow turbines were uprated to 10,000 hp
   (7.5 MW). This may stem from the fact that at sea level the turbines
   could produce that much power. The electrical equipment, however, could
   only handle 8500 hp (6.3 MW). Also, the turbines in revenue service
   always operated above sea level. Even so, the turbine design used in
   these units is still the most powerful prime mover ever installed in a
   locomotive.
   Turbine fuel tender.
   Enlarge
   Turbine fuel tender.

   Bunker C's cost advantage waned as the plastics industry began to find
   uses for it and improved "cracking" techniques allowed the oil (which
   had previously been considered waste) to be converted to lighter fuel
   grades. The oil crisis in the 1970s and the rise in fuel costs
   highlighted the inefficiency of the turbines. All were out of service
   by 1970. Their running gear was recycled into the GE U50 series of
   locomotives. Parts from units 51 to 75 were used to make the U50, and
   parts from units 1 to 30 were used to make the U50C.

   Two of the turbines survive - UP 26 in Ogden, Utah, and UP 18 at the
   Illinois Railway Museum. Several of the tenders were retained and
   converted to hold water for use with Union Pacific's operating steam
   locomotives, UP 844 and UP 3985.
   UP 80, the failed coal-fired turbine.
   Enlarge
   UP 80, the failed coal-fired turbine.

   In October 1961, Union Pacific constructed an experimental GTEL of
   their own, using an Alco PA-2 as a cab, the chassis of a GE W-1 class
   electric locomotive (bought for scrap from the Great Northern) as the
   second unit, and an modified turbine prime mover from the 50 to 75
   series. The setup was numbered 80, but changed to 8080 in 1965 to avoid
   conflict with the EMD DD35s being introduced. The bizarre-looking
   consist had a bizarre wheel arrangement as well: A1A-A1A+ B-D+D-B, i.e.
   18 axles of which 16 were powered. A "centipede" steam locomotive
   tender was rebuilt with a coal crusher to pulverize and feed the coal
   to the turbine. Power output was estimated at 7000 hp (5.2 MW). The
   original diesel engine in the PA was retained and produced 2000 hp (1.5
   MW) and the turbine produced the additional 5000 hp (3.8 MW). The blade
   erosion and soot buildup problems encountered in the earlier
   locomotives were magnified with UP 80/8080. Grinding coal into fine
   particles was also troublesome. Any oversized coal particles could
   damage the turbine blades. Ultimately, UP 80/8080 was declared a
   failure, and this "contraption" was dismantled. The conventional gas
   turbines each racked up well over a million miles in revenue service,
   by comparison the coal turbine prototype ran less than 10,000 miles
   before being stricken from the UP roster.

   UP 26 photographed by Jim Munding, all others courtesy of Don Ross

Other GTELs

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

   Union Pacific was not the only user of GTELs. United Aircraft built the
   Turbo passenger train, which was tested by the Pennsylvania Railroad
   and later used by Amtrak and VIA Rail.

   SNCF (French National Railways) uses 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.

   The British Rail APT-E, prototype of the failed Advanced Passenger
   Train, was turbine-powered. Like the 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.

   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. A
   number of refurbished RTL IIIs are currently in service.

   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.

   Retrieved from "
   http://en.wikipedia.org/wiki/Gas_turbine-electric_locomotive"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
