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Union Pacific GTEL Locomotives

In the early ‘50s, General Electric (GE) and the now defunct American Locomotive Company (Alco) teamed up to build a number of immensely powerful gas turbine locomotives that were icons of the American West for nearly three decades. 

Though they’d never been used in trains, the revolutionary gas turbines provided more than enough power to pull huge loads through some of the country’s most mountainous terrain, and in many respects they outclassed the diesels that had been the mainstays of the industry since the turn of the century. 

But despite admirable service and remarkable performance, the gas turbine-electric locomotives – or GTELs – lives were cut short due to rising energy costs, high fuel consumption, and stiff competition from a new breed of increasingly powerful and efficient diesels.

It’s a classic tale of innovation and economics, and more importantly, the never ending quest for more horsepower. 

Now, the Union Pacific GTELs.

A Brief History of the Locomotive

The first gas turbine locomotive was built by Renault in 1952.

With a few minor variations, gas turbine power plants were remarkably similar to the jet engines becoming more common in the aircraft of the era.  

With just 1,000 horsepower Renault’s locomotive wasn’t exactly a heavyweight, but across the Atlantic in the United States much bigger machines were on the drawing board.

In fact, the Union Pacific (UP) would eventually operate more GTELs than any other railroad in the world, and some had eight times as much horsepower as their French counterparts. 

That said, locomotives had been around for ages by the time the gas turbine monsters burst onto the scene. 

The machines that preceded the GTELs were powered first by steam and later by diesel engines, though the two operated side-by-side for decades. 

First-generation GTEL and a 1923 electric auto in Fremont, Nebraska in 1953.

Steam engines were introduced in 1802 when English engineer and tinkerer Richard Trevithick built a newfangled power plant that he installed in a rickety locomotive.

Called a High-Pressure Tram Engine, Trevithick boasted that his invention produced sufficient power to haul “ten tons of Iron, five wagons, and 70 Men.” 

It took more than four hours to cover just nine miles (14.5 km) ,but as they say, Rome wasn’t built in a day.

Nonetheless, the engine set an avalanche of innovations in motion that would change rail transportation forever. 

The pinnacle of steam technology was reached nearly 150 years later when the Union Pacific ran a fleet of 25, 7,000+ horsepower Big Boy locomotives between Utah and Wyoming. 

By comparison, most diesels of the day cranked out about 1,500 horsepower.  

But though they were brimming with brute strength, steam engines were heavy, expensive, and prone to catastrophic boiler explosions.

Enter the Diesels

Diesel locomotives began showing up in numbers in the 1920s, but most were restricted to flat routes and yard duty because they just didn’t have the “cajones” to hack it out on the mainline where the loads were heavy and large changes in elevation were common.  

In fact, many had less than 1,000 horsepower, which meant that when they did venture out they were often used in groups of two or three.  

Over time mechanical engineers squeezed more and more “umph” from diesels, but few would ever make anywhere near the horsepower that the Big Boys and GTELs did. 

However, thanks to their low maintenance and operating costs, they eventually became the biggest players on the railroad scene, and they still are today.

In England however, it wouldn’t be until after the Second World War that the first diesel locomotives entered mainline service.   

On the other hand, by the late ‘30s in America, big diesel-electric locomotives were everywhere, and many looked like art-deco masterpieces. 

Big, sleek, and emblazoned with colorful paint jobs, they were sights to behold. 

But sadly, they were still lacking in the one area that mattered most – horsepower. 


In their search for better power solutions, UP tested and ultimately rejected a pair of steam turbine locomotives in the ‘30s.  

Diesels were getting the job done, but using three or four expensive locomotives to do jobs that might be done by one more powerful unit had UP accountants and shareholders seeing red. 

GE had been building gas turbines for various propulsion and power generation applications for years, but again, they’d never been used in locomotives, because who in their right mind would put a jet engine in a train?

Then, somewhere – perhaps in Union Pacific’s Omaha, Nebraska headquarters – a light bulb went off.

The idea had some merit, but there was one huge problem. 

Gas turbines inhaled fuel like pensioners gobbled shrimp on “Seafood Night” at convalescent centers. 

In fact, turbines used twice as much fuel as diesel engines, but if one of the former could match the power of two or three of the latter, fuel expenditures could actually be reduced. 

And the diesels would then be freed up to haul revenue-generating freight elsewhere, like on flatter routes where the loads weren’t so heavy. 

In addition, gas turbines tended to be most efficient when operating at high speeds over long distances.  

They’d slow considerably when tugging heavy loads through mountain passes, but the West was full of wide-open spaces and flat ground too, so it was a natural fit.  

Alco-GE produced the prototype GE 101 in 1948, and UP put it through its paces until the following summer when it was redesignated UP 50. 

Gas turbine-electric locomotive, Union Pacific 18 at the Illinois Railway Museum.
Gas turbine-electric locomotive, Union Pacific 18 at the Illinois Railway Museum, GE 101 1948 Demonstrator Prototype. By JeremyA, is licensed under CC-BY-SA

Though fuel economy was poor, it wasn’t a big deal considering the power UP 50 produced, especially since it burned Bunker C heavy fuel oil which was significantly less expensive than diesel. 

On the downside, Bunker C was dirty and coagulated into a molasses-like glob in low temperatures.  

To remedy this, it had to be heated by a steam generator before being injected into the turbine’s combustion chambers. 

Later, heaters were built directly into the tenders, but keeping the viscous fuel flowing was always a hassle. 

Eventually UP switched from Bunker C to more refined #6 heavy fuel oil which burned more cleanly and caused less turbine blade wear – the latter of which was a constant issue for the GTELs. 

Its biggest drawback however, was that #6 heavy fuel oil was expensive. 

This was partially offset by giving the new engine the air it needed in greater quantities. 

Adjustable louvers were added that were capable of optimizing airflow depending on temperature, load, terrain and wind conditions.

Union Pacific intended to use the new gas turbine locomotives to replace its Big Boy steamers which were already scheduled to be mothballed. 

Though it performed well, the railroad never actually took ownership of UP 50, but most of its design features were incorporated into later models. 


Spanning more than 80 feet (25 m) from end to end and tipping the scales between 550,000 (230,000 kg) and 850,000 pounds (385,550 kg) depending on generation, the GTELs were big machines. 

Featuring four multi-axle trucks and a track gauge (width) of about 4.5 feet (1.37 m), the steel behemoths were capable of hauling loads approaching 7,000 US tons (6,350,290 kg) across particularly vast stretches of country peppered with long, steep grades. 

But all that power wasn’t distributed through a transmission and drive shaft like it is on cars and trucks. 

Instead, mechanical energy from the engine was converted into electricity by massive alternators, after which it was transmitted to traction motors (electric motors) at the wheels that provide the propulsive force to get and keep the gargantuan machines moving. 

This efficient if complex system worked well in locomotives, and over the life of the GTELs output more than doubled, ultimately ending up at about 8,500 horsepower – at least officially. 

Tractive effort – the amount of force exerted on the drive wheels – in first-generation units was an astonishing 138,000 pound-feet, or roughly the same pulling power generated by 100 heavy-duty European or American trucks.  

The maximum speed for early GTELS was 65 mph (105 km/h) on level ground, though they were capable of going much faster.  

First Generation

Between January 1952 to August 1953, UP received ten GTELs from Alco-GE. 

At about a half a million USD a pop (about 5.2 million USD today) the locomotives were similar to the UP 50, with the exception that they only had a cab at one end.

This design change increased fuel capacity to 7,200 US gallons, which came in handy since the new GTELs were pullinging freight between Green River, Wyoming and Ogden, Utah.

By the time they’d been “broken-in” in 1954, the GTELs began covering other Western routes too, and the following year to compensate for their high fuel consumption, 24,000-US gallon (91,000 L) fuel tenders were added behind the locomotives.

This setup extended their range sufficiently to allow them to make the 900-mile (1,448 km) run between Ogden, Utah and Council Bluffs, Iowa. 

During this time a new roof-mounted intake system was also tested to provide the engines with more air for cooling and increased combustion efficiency. 

Successive locomotives were built with this new feature, and UP also converted one unit to run on propane which was fed to the engine from a huge pressurized tank on a separate tender car. 

Propane burned cleanly and didn’t foul the turbine blades like the thicker and less refined fuels did, but it was more expensive and presented additional handling, transportation and safety concerns. 

In the end, the savings just weren’t worth the headache, and the experimental unit was ultimately converted back to operating on Bunker C.

Later, two units were used in tandem with a fuel tender between them, but though the combination purportedly made well over 10,000 horsepower, the second locomotive’s turbine often experienced a compressor stall in tunnels due to the ingestion of exhaust from the unit in front of it. 

Modifications were made to remedy the problem, but the scheme was nixed in favor of a GTEL-diesel setup which proved more reliable and fuel efficient, while still sending about 6,500 horsepower to the tracks. 

Second Generation

The first of more than a dozen second-generation GTELs was delivered to UP in early 1954. 

Nicknamed “veranda” units because the engine housing was narrower than the locomotive itself, each featured two side walkways that gave them distinctly different looks made it easier for crewmen to get from the cab to the engine bay.

The engines, traction motors, air intakes and other components on second generation units were similar to those on earlier models, but the loads had become so immense that nearly all units were now used in tandem with a diesel locomotive.  

Third Generation

After the success of the previous generations of GTELS, Union Pacific ordered 30 new and even more powerful units in the mid-’50s. 

Though it’d be years before they’d take possession of the first, it and its successors would go on to become the world’s most powerful locomotives.  

Each consisted of two units, one gas turbine engine, and a 24,000 US gallon (91,000 L) insulated fuel tender.

The first – or A – unit housed the cab, auxiliary generator, and other secondary systems, while the B unit carried the turbine and electricity generator which sent power to traction motors in both units. 

Delivered to Union Pacific in August of 1958 with an official rating of 8,500 horsepower, UP engineers and mechanics claimed that the new beast produced over 10,000 horsepower when operating in cooler denser air. 

Meanwhile, tractive effort rose by about 10% to 146,000 pound-feet. 

By the early ‘60s weight ratings had grown to between 5,200 and 6,700 tons depending on route, with the former being the limit for mountainous areas.   

The new turbines featured 16-stage compressors for more efficient intake and combustion, but with full tenders each supersized GTEL weighed a staggering 1.2 million pounds (544,310 kg). 

In fact they were so heavy that UP considered adding traction motors to the fuel tenders, though it wouldn’t be done until years later when routes to Los Angeles were added. 

Now in addition to tenders being motorized, speed restrictions were imposed to improve safety, conserve fuel, and reduce stress on the mechanical and electrical systems. 

Since clogged filters were constant sources of aggravation, a number of GTELs began running exclusively on pre-filtered fuel. 

This made the engines cleaner, more efficient, and more powerful while reducing blade wear, but by 1970 all of the third-generation GTELs had been retired. 

Experimental Coal Burner

In October of 1962, Union Pacific built a Frankenstein-like GTEL using an old cab purchased from the Great North Railway and a tweaked gas turbine from a first-generation locomotive. 

Featuring two units, 12 powered axles and a 2,000 horsepower auxiliary diesel engine, the experimental unit cranked out a respectable 7,000 horsepower, but injecting coal dust into the combustion chamber of a gas turbine wasn’t without problems.  

Despite what energy executives say these days, coal isn’t particularly clean, and it was even dirtier more than a half a century ago when engines were much less efficient. 

In fact, the blade erosion and soot emission problems so common with Bunker C fuel were amplified to the point that the increased maintenance costs more than negated the savings from using cheap coal as energy. 

Ultimately, after spending less than two years in service, the old hybrid locomotive was laid to rest and later cannibalized for spare parts. 

The End of the GTELs

For decades, early and late model GTELs ran alongside one another in Western states like Wyoming, Utah and New Mexico. 

UP officials claimed that during the ‘60s the GTELs hauled as much as 10% of the company’s freight, though they made up far less than 10% of power units by number. 

Even today, they’re the most powerful engines ever installed in North American locomotives. 

All told, the gas turbines traveled tens of millions of miles, and production ran from January of 1953 to the summer of 1961, with 55 units being built and delivered. 

But though the third-generation units were still operating in the late ‘60s, the writing was on the wall. 

Diesels were becoming more powerful and a national fuel crisis was looming 

Between 1949 and 1967 the average price of gasoline and other fuels in America remained relatively static. 

There were slight yearly variations, but things were about to change, and by the late ’70s the average cost of many refined fuels had nearly tripled. 

Hence, fuel efficiency became a huge factor in deciding which engines to use. 

Sadly for horsepower junkies and train geeks, the GTELs were no longer economically viable.  

The gas turbine’s last hoorah took place the day after Christmas in 1969. 

Now more than 50 years later a few GTELs have been lovingly restored by railroad museums around the country, but though they may look new on the outside, the cost of renovating their engines and running gears is prohibitively expensive, so the chances of them ever again thundering down the tracks are slim to none. 

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