Union Pacific GTELs - Third Generation

Third Generation

In 1955, Union Pacific announced that they were ordering a new model of turbine-electric. This would become the world's most powerful locomotive. Each locomotive would consist of two units plus a fuel tender, rated at 8,500 horsepower. These units were equipped with a new design GE Frame 5 simple cycle gas turbine engine, with a sixteen-stage compressor, ten combustion chambers and a two-stage turbine. The leading A unit contained the control cab and an auxiliary diesel engine generator. No steam generator was needed because insulated tenders were used. The B unit carried the turbine prime mover and the main generator to provide electricity to the traction motors on both front units. The original plan was to number these units in the 7000 series but they were numbered 1 to 30. They were delivered to Union Pacific between August 1958 and June 1961. These units were very different from the previous generations, consisting of a wheel arrangement of C-C on each of their units (not including their fuel tenders).

The locomotive weighed 900,000 lb (410,000 kg), not counting the tender, and had a maximum starting tractive effort of 240,000 lbf (1,100 kN).

These locomotives, generating 8,500 hp from a single prime mover, set a record which stands to this day. Like the Big Boys, the turbine locomotives had their own nickname on the UP, railroaders called them "Big Blow" because of their roaring jet-engine exhaust.

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.

The Big Blows often hauled trains weighing over 13,200 short tons (12,000 t) between Council Bluffs, Iowa and Ogden, Utah. Unlike the earlier turbines, the 8500 hp turbines were designed from the outset to use 24,000 US gallon (91,000 l) fuel tenders, in addition to the 2,500 US gallons (9,500 l) of diesel fuel in the locomotive fuel tank. These locomotives came equipped with Leslie S-5T-RF air horns located on the cab roof (later moved to the mid radiator section of the A unit in response to ice build-up in the bells).