The Most Powerful Locomotive In America Was So Loud It Was Banned From Cities And So Hot It Melted Pavement. Here’s A Close Look

I’ve been spending a lot of time visiting the largest railroad museum in America, the Illinois Railway Museum. Through all of my visits, one locomotive has caught my curiosity more than any other thanks to its sheer size, power, and insanity: Union Pacific’s Gas Turbine-Electric Locomotive, or GTEL. The locomotive is not only the most powerful built in the United States, but the turbines behind that power produced a deafening roar and heat that cooked birds and bridges.

A Quest For Power

As the Illinois Railway Museum notes in its history of the Union Pacific’s Gas Turbine Locomotive, the trains came out of the Union Pacific Railroad’s quest for more power. The railroad started experimenting with turbines back in the late 1930s; in April and May 1939, the railroad tested a pair of steam turbine-electric locomotives that were produced in a collaboration with General Electric. At the time, train history site Utah Rails notes, Union Pacific was looking for a replacement for steam and something more advanced than the diesels of the day. The steam turbine-electric locomotive used an oil-fired boiler to produce steam to turn a turbine. That turbine was paired with a generator,  and tractive effort was achieved through electric motors. The locomotives looked on the outside like the diesels of the day.

Ultimately, the steam turbine-electric locomotives proved to be unreliable, sometimes encountering failures that required other kinds of locomotives to finish the journey. The turbine-electrics never entered regular service and were returned to GE in June 1939. UP kept the collaboration going for another two years before deciding to stop chasing the technology. Right around this time, the railroad entered its now famous Big Boy steam locomotives into service, and it wouldn’t even be a decade before Union Pacific would flirt with different technologies for locomotives again.

As Utah Rails writes, Union Pacific was still hungry for power. In 1946, it had 154 diesel-electric locomotives on hand, but none of them were in freight service. Instead, the railroad saw success in running its Big Boy steamers in freight use. UP, like other railroads, began looking into how it could adapt diesel for freight. But there was a problem: a Big Boy could produce about 7,000 horsepower at 70 mph, yet a typical diesel of the day like an EMD F3 or an Alco FA produced about 1,500 horsepower. To get diesels to near or equal the amount of power as a steamer, locomotives were lashed up with power units and the whole thing was controlled from the cab. Here’s an example of what this looks like:

According to Diesel Power Magazine, Union Pacific closely watched fuel prices and wasn’t fond of the price of diesel. In addition, those diesels required expensive maintenance. The railroad wanted a cheaper solution.

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General Electric Develops A Gas Turbine-Electric Engine

Around this time in the latter part of 1940s, General Electric used what it learned in aviation and restarted development on gas turbines for locomotives. Union Pacific, seeing the potential for lower running costs, wanted in. GE partnered up with manufacturer American Locomotive Company, or Alco, and in 1948 the companies put a beast into testing. Initially tested on the New York, Chicago and St. Louis Railroad and the Pennsylvania Railroad, the Alco-GE number 101 produced 4,500 horsepower and looked like a diesel.

A year later, the unit would be transferred to Union Pacific, where it became unit 50. Over the span of nearly two years, UP put over 100,000 miles on the locomotive, taking it all over the rail line. The railroad was impressed enough with the unit that before number 50 was returned, Union Pacific ordered ten of them. Number 50 went back to GE in 1951 and a year later, the railroad got the first production units.

How The GTELs Work

How these locomotives work is similar to a diesel-electric, but with a different kind of engine. Union Pacific’s GTELs used a GE Frame three-turbine engine to drive a generator. That generator produced electricity, which found its way down to the traction motors.

Another difference between a diesel and the turbine units was the kind of fuel used. The GTEL units were fueled using heavy fuel residual oil. Documents from Union Pacific and General Electric note that fuel to be Bunker C, a black heavy fuel that has the consistency of molasses at room temperature. This meant that the fuel had to be heated to provide a reliable flow to the turbine. To achieve this, heaters were installed into the locomotive’s fuel tanks to warm the sludge to 200 degrees.

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The residual oil was also too heavy for the turbine to start. Thus, the starting procedure involved using the locomotive’s auxiliary diesel generator to spin up the turbine. The turbine would then start on diesel. Then, after the turbine was running fast enough it would be fed the heavy fuel oil.

Huge Fuel Tanks

This is really only the start of the oddities with these locomotives. Six of the first-generation 4,500 HP units pulled in air through huge side louvers that could be opened and closed depending on need. But engineers found that this air intake design meant power loss from the heating of the air. And the compressor blades got coated in oil and dirt. This led to a design change, moving intakes from the sides to the roof. These first locomotives had a fuel capacity of 7,200 gallons, or enough fuel to haul a load between Green River, Wyoming and Ogden, Utah.

Union Pacific later took steam locomotive tenders and modified them into huge 24,000-gallon tenders for the GTELs. These extended the range of a GTEL enough so that they could travel the 990-mile route between Ogden, Utah and Council Bluffs, Iowa.

Union Pacific also considered a route from Salt Lake City to Los Angeles. However, according to an American Rails history linked by UP, the locomotives were so loud that some California cities banned them. As you would expect, a turbine engine makes a deafening roar regardless if it’s powering an aircraft or a train. Thus, as UP says, its GTELs earned the nickname “Big Blows” for their sound. Through UP GTELs’ entire run, the trains marched through farmlands and mountains where the noise and the smoke had fewer people to bother.

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These Locomotives Terrorized Cities

And that sound is something else. I haven’t been able to find a clean sound clip, but the best one that I’ve found is from Railfan Depot on YouTube:

In the video, the narrator explains that Union Pacific’s GTELs, steamers, and diesels would join forces to climb up to the 8,014-foot summit on the Sherman Hill line in Wyoming. Originally built as part of the Transcontinental Railroad, trains crossed the Continental Divide through a steep up to 1.92 percent climb up to a summit of 8,247 feet. Union Pacific worked through the decades to reduce the height of the climb and the grade. A line through Cheyenne and Buford reduced the grade to 1.55 percent. And by 1953, the Harriman line reduced the grade to 0.8 percent by making trains take a longer, gentler route.

The video shows GTELs pairing up with steamers and diesels to power their way through the mountains. While the sound clip isn’t the clearest, in the video it sounds like a rumble of thunder. If you listen closely, you can then hear the sound of a steamer or diesel being drowned out by the thing. Big Blow seems pretty accurate.

And GTELs were more than just loud. As train history site American Rails notes, the turbines burned fuel at 1,400 degrees Fahrenheit in their combustion chambers, and under a full load, exhaust fired out of the locomotive at 150 mph with temperatures as high 850 degrees Fahrenheit. The exhaust was so hot that as the Utah State Railroad Museum notes, it caused some chaos:

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The turbines had several nicknames, among them “Bird Cookers” as the engine emitted a huge column of superheated exhaust that would consume birds in flight. They also had a tendency to quickly consume oxygen in tunnels, which caused overheating and asphyxiation. When a turbine was placed on a train going east out of Ogden, the yard switcher would push the turbine under the Riverdale Road underpass to start. The turbine would flame out, and the pavement on the overpass would melt and sometimes ignite from the huge amount of heat.

You’d think that between the need for heated bunker fuel, 24,000-gallon tenders, and heat hot enough to grill a bird mid-flight that the gas turbine-electric trains were a horrible investment for Union Pacific. However, according to Utah Rails, at first it was the opposite. The railroad was impressed enough with the first ten (UP 51 through UP 60) that in 1954, it ordered fifteen more (UP 61 through 75). These second-generation gas turbine-electric locomotives had the similar spec sheet as the first-generation, but sported a different body. While the first-gens had a more traditional carbody style, the second-generations gained crew walkways like a hood unit would have. These locomotives would come to be known as “Veranda” units.

Another development in GTELs at this time was that the lead unit could control trailing units, though just 19 of them were apparently set up in that configuration. As the video above shows, trailing units were often diesels.

The GTELs Were Legitimately Good For Union Pacific

For a while, the GTELs padded UP’s bottom line. As Utah Rails notes, Steam power cost UP $145.14 per 1,000 gross ton-miles, while diesel ran at $84.03 per 1,000 gross ton-miles. But the GTELs, with their cheap Bunker C? They ran at $69.19 per 1,000 gross ton-miles. However, as Diesel Power Magazine writes, to maintain these cost savings the turbines couldn’t be allowed to idle. They had to be pulling a load at full power to be the most economical for the railroad. Utah Rails notes that UP was running GTELs 8,000 miles and 400 hours per month, and they were available 78 to 80 percent of the time.

In 1956, Union Pacific published Six Million Miles Experience With Gas Turbine Locomotives. In it, the railroad describes what its then 25 GTELs had achieved. The big thing, as suggested by the title, is that the locomotives had collectively traveled six million miles in four years. Together, the engines fired 227,950 hours, with one turbine clocking in at 17,266 hours all on its own.

In the document, the railroad described the locomotives as getting 360 feet per gallon at an average of 33 mph. The railroad goes on to note that as an example of the endurance of its gas turbines, in 1955 a whole ten percent of UP’s freight was pulled by a GTEL. And the GTELs moved 38.5 percent of the freight in their assigned division. The document also notes experimentation with different fuels and fuel qualities, including a locomotive that ran on propane.

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Riding on the success of the 4,500-HP units, Union Pacific placed yet another order for gas turbine-electric locomotives. These would become not only the most ridiculous of the bunch, but the most powerful locomotives built in America. UP placed its order in 1955, but development problems delayed their deployment until 1958.

A Major Design Overhaul

Numbered 1 through 30, the final run of UP GTELs saw a major design overhaul. The previous two generations of GTEL featured the locomotive and a tender. These third-generations? They came in three sections. Up front was a control cab that contained a Cooper-Bessemer FWB-6 850-HP diesel engine. This engine provided auxiliary power, as well as power to move the control unit around in a yard. Bringing up the rear was one of the 24,000-gallon tenders. And in the middle? A GE Frame 5 turbine kicking out 8,500 horsepower at an elevation of 6,000 feet. At sea level, it’s believed that the turbine could do even better, putting out 10,000 horses. However, it’s noted that the generator was rated for 8,500-HP.

That massive gas turbine unit powered four generators, which in-turn powered 12 traction motors. The control cab had six motors, as did the turbine unit. This turbine still fed off of fuel oil that needed to be heated, and this was done electrically in the 24,000 gallon tender.

The Illinois Railway Museum says that the whole 165-foot, 11-inch consist weighs in at 849,248 pounds. Though some estimates say that loaded down with fuel, these are well over a million pounds. No matter how you look at these locomotives they’re simply gargantuan. But for more numbers, a third-generation GTEL produces 240,000 pounds starting tractive effort, and 145,000 pounds at 18 mph. That is up from 105,000 pounds in the previous generation.

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These locomotives thundered their way through America’s open west, hauling heavy freight, and cooking birds.

GTELs Weren’t Perfect

However, Union Pacific did face some problems with its gas turbine-electric locomotives. One noted problem came from the burning of Bunker C. The ash content–containing sodium and vanadium–of the gas flow corroded combustor cans, nozzle vanes and turbine blades. As Turbo Machinery Magazine reported, the nozzles and first stage blades were made of a high nickel Nimonic 80A alloy, an expensive high temperature material. To slow this down, engineers used epsom salt and water to neutralize some of the effects. This improved reliability, but the time between overhauls was still between 4,000 and 5,000 hours.

And it wasn’t just expensive maintenance that was problematic for the GTELs. As the Utah State Railroad Museum notes, the turbines burned twice as much fuel as a comparable diesel. However, they won out on operating costs by running cheaper residual fuel. That cost benefit didn’t last, as developments in refining processes improved, wastes were able to become finer grades of fuel. Eventually, the cost of heavy fuel began rising, and with time, the maintenance and fuel costs caught up with the GTELs. Union Pacific began phasing them out in 1968, and the turbines hauled their last miles in 1970. Some of them didn’t even get to see a decade on the rails. The railroad admits that it made no effort to save the units.

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GTELs Eventually Disappeared

Ten of the 8,500 HP units were sold to Continental Leasing Group, with 20 going back to General Electric. In both cases, the locomotives were stripped of useful parts then scrapped. Some trucks found homes under other locomotives while the turbines found other industrial uses. Somehow, two units escaped the scrapper, with UP 18-18B getting donated to the Smoky Hill Railway and Historical Society in 1977. The Illinois Railway Museum then became its caretaker in 1993.

UP 26-26B was donated to the Ogden Union Station Museum in Utah in 1986. Sadly, both locomotives were stripped of parts before they were able to be saved. UP 26-26B is just a shell. UP 18-18B at IRM is more complete, but is missing its turbine. Both locomotives have gotten cosmetic restorations, but it appears that neither will roll under their own ridiculous power again.

As for Union Pacific, it still continued its quest for more power. After the end of the GTELs, the railroad turned to diesel. In 1968 UP tried to fulfill its power needs with 50 EMD SD45s. These locomotives featured EMD 20-645E3A V20 engines generating 3,600 HP. The SD45s were good, but not enough for the railroad. Union Pacific reached out to EMD for more power, and the result was the behemoth EMD DDA40X.

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Often cited as both the largest and most powerful diesel-electric locomotive ever built, the 98-foot, 5-inch, 475,830-pound machine is staggering. The prime movers are a pair of EMD 16-645E3A diesels. These 169.6-liter V16s made 3,300 HP each, for a combined total of 6,600 HP. And those engines are fed from a massive 8,000-gallon diesel tank integrated with the locomotive’s frame.

But even these saw retirement after UP encountered high maintenance costs.

Today, the gas turbine-electric locomotives are remembered for their pure insanity. And it’s sort of amazing that Union Pacific was able to run gas turbines for more than two decades. To date, these remain the most powerful locomotives ever built in America. And despite their issues, it’s noted that each GTEL managed to travel at least a million miles before retirement.

(Photo credits to the author unless otherwise noted.)