America’s most powerful locomotive was so extreme that cities had to ban it: Jalopnik

It was the 1950s, a post-war transition period in which road transport was still gaining momentum and the railways were doing the heavy lifting. Steam engines were on the way as diesel locomotives gained a foothold in railway logistics.

However, Union Pacific, an American railroad conglomerate, saw things differently. Obsessed with the “Gross ton-mile per train hour” formula that calculated transportation efficiency, it wanted a torque monster that would replace several locomotives needed to pull a long convoy of coal cars up a mountain without breaking a sweat. The answer was the Gas Turbine-Electric Locomotive (GTEL), which seemed to defy the laws of physics with its cost-efficiency and sheer power.

The need for such a monster was simple: power density. Diesel-electric locomotives outperformed steam engines, but were bulky and produced only 1,500 horsepower. One of the biggest challenges for Union Pacific was pulling heavy loads through terrain such as the Wasatch Grade, a 65-mile climb with a 1.14% gradient through Utah’s Wasatch Mountains. It was one of the reasons Union Pacific developed the 4-8-8-4 “Big Boy” steam locomotive. Even on flatter routes it was not unusual for a convoy of 200 cars to be moved by as many as five diesel locomotives.

This need for efficiency led Union Pacific to develop the GTEL. The railroad wanted more power per axle, and the GTEL delivered four times the power of a diesel-electric locomotive—enough to haul a 5,000-ton rail convoy over the Wasatch Mountains without breaking a sweat. But it had a downside: it was so loud, powerful and hot that some cities wouldn’t let it through.

Then came the running sequence. The GTEL was a two-piece monster, with the “A” unit housing an auxiliary diesel engine, while the massive “B” unit carried the turbine and generator. To start a GTEL, the diesel auxiliary was activated, cranking the turbine until it reached self-sustaining speeds. Fuel and compressed air were used to move the engine. This mixture was ignited and the resulting hot gases expanded, setting the turbine blades and drive shaft in motion. This driveshaft powered a generator which in turn sent power to eight electric traction motors.

Third-generation GTELs could produce more than 10,000 horsepower, but were limited to 8,500 horsepower to prevent the electrical generators from melting down. To keep the turbine running, a specialized tender carrying 24,000 liters of fuel was attached to the GTEL. This fuel not only helped provide virtually unlimited pulling power, but also offered significantly cheaper operations (on paper). It wasn’t diesel or petrol.

In the 1950s, Bunker C was considered a waste byproduct of refineries and was therefore cheap. At the time, it was the most cost-effective way to move over 10,000 tons of freight, provided the turbine remained at full load. That’s because the GTEL turbine was efficient at full throttle, but consumed almost the same amount of fuel at idle. Although Bunker C was cheap, the quantity consumed was enormous and the 24,000 liter fuel tender could quickly run out.

The GTEL’s low operating costs were based on the ready availability of industrial waste fuel, a gamble that paid off well until the oil industry found other ways to use Bunker C. In the meantime, to keep the engine at maximum efficiency, the GTEL engine crews kept it running at full throttle all the time. And this was a big problem.

GTEL trains could be heard from a great distance, and chances were you not only heard it coming, but felt it in your chest long before you actually saw it. The noise emanating from the turbines at operating speed was so piercing that the GTEL crew used the auxiliary diesel engine to move the locomotive around the yard. This noise caused many problems for Union Pacific, especially when GTELs entered a town or city.

Another problem was the heat. As the trains passed under low-hanging railway bridges, the intense heat could melt the asphalt. Birds flying over the locomotive and through the black exhaust plume would be burned, earning the GTEL another nickname: “Bird Cooker”. (Still, it wasn’t as crazy as Daddy Long Legs, a wild high-rise train equipped with lifeboats.)

Under pressure from residents, most California cities banned GTELs, and Union Pacific was forced to limit their use to remote areas between Council Bluffs, Iowa and Ogden, Utah. However, California’s bans were not the main reason for GTELs’ demise.

The first was the very thing that had made the GTEL financially viable: Bunker C fuel. Bunker C was initially so cheap that, despite the enormous thirst of GTELs, they were more cost effective than a bunch of diesel engines. However, by the late 1960s, companies had begun using Bunker C fuel to make plastics, and had learned that it could be broken down to make lighter fuels. A fuel residue that was easily available became rare, prices skyrocketed and running the GTEL on Bunker C became prohibitively expensive.

The second problem was reliability. While you use several smaller diesel engines, you can get away with a breakdown. On GTELs, turbine failure meant the entire train was dead. GTEL turbine blades required constant maintenance due to the corrosive nature of Bunker C fuel, and the engines required a separate maintenance facility and service personnel with the technical knowledge to maintain jet engines.

Rising fuel and maintenance costs prompted Union Pacific to pull the plug on the GTELs in 1970. Of the 55 GTELs made for Union Pacific over two decades, only two remain today, parked at railroad museums. GTEL number 18 is located at the Illinois Railway Museum in Union, Illinois, and GTEL number 26 is located at the Utah State Railroad Museum in Ogden, Utah.