Union Pacific GTELs

Union Pacific operated the largest fleet of gas turbine-electric locomotives (GTELs) of any railroad in the world. The prototype, UP50 was the first in a series built by Alco-GE for Union Pacific's long-haul cargo services. The prototype was introduced in 1948 and was followed by three series of production locomotives. These locomotives made up 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 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. They were operated into the 1970s, when rising fuel costs made them uneconomical.

Prototype

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.

After Union Pacific expressed interest, Alco-GE built a prototype, GE 101, which was completed in 1948. 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.

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

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.

First Generation

Units 51 to 60 were delivered to Union Pacific beginning in 1952. Nicknamed "Big Blows" because of their high noise levels,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). The tenders were also equipped with MU connections so that trailing locomotives could be controlled as well. As tonnage requirements increased, utilizing additional diesel locomotives for multiple unit operation became more commonplace.

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.

econd Generation

Units 61 to 75 were delivered to Union Pacific beginning in 1954. 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.

Third Generation

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.

Retirement

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.

wheel arrangement, "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 the coal turbine. Grinding coal into fine particles was also troublesome. Any oversized coal particles could damage the turbine blades. Ultimately, the experiment was declared a failure and was scrapped. 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 [http://donsdepot.donrossgroup.net Don Ross] "

References

* [http://www.uprr.com/aboutup/history/loco/locohs05.shtml Historical UP locomotives: Gas turbine locomotives]
* [http://www.northeast.railfan.net/pro_faq2.html#turbine Gas Turbine locomotive FAQ]
* [http://www.northeast.railfan.net/turbine_faq.html Gas turbines FAQ - NE Rails]
* [http://utahrails.net/up/diesels/up-diesel-story-1934-1982-c.php Union Pacific story 1934-1982 part 3]
* [http://www.railpower.com/2support/locomotives.htm Locomotive Engineers Journal; July, 1949]