GE "U50" Locomotives: Specs, Horsepower, History
Last revised: January 1, 2025
By: Adam Burns
The U50 was one of the most powerful single unit road switchers General Electric ever produced. During the great horsepower race sparked by Union Pacific in the 1960s, all three builders produced incredibly powerful road-switchers.
It was UP's attempt to reduce operating costs by increasing the power of a single unit. All seven examples (GE's U50 and U50C; Alco's C855; the joint Alco/GE gas turbines; EMD's DDA40X "Centennial" and DD35/A; and Alco's DH-643 diesel hydraulic) featured horsepower ratings between 4,300; 5,000; 5,500; and 6,600.
History
Unfortunately, most, including the U50, were hampered by reliability issues since they were essentially two locomotives stuck under a single hood.
The speed at which they were designed and manufactured meant research and development was not properly carried out, save for EMD's variants.
The GM subsidiary already provided a well-established catalog, featuring the model 567 and later 610 diesel engines.
As a result, its DD35/A, and especially the DDA40X, were actually relatively successful. The latter rolled up millions of miles in service before the fleet was finally retired in the 1980's.
Today, all examples of the U50 built for UP, along with the three acquired by Southern Pacific, have been scrapped.
Photos
A Union Pacific publicity photo featuring three new U50s in Omaha, Nebraska, led by #32, during 1963.Union Pacific
The U50 was essentially an experimental, high horsepower diesel locomotive, originally requested by Union Pacific in the early 1960s.
UP was attempting to reduce operating costs by using high horsepower locomotives, which would reduce the number of units needed per train.
The railroad's interest in such locomotives dated well back to the steam era with the incredibly powerful 4-8-8-4 "Big Boys" from American Locomotive.
Then, in 1952 Alco collaborated with GE to construct the gas turbine electric locomotive (GTEL) that offered phenomenal horsepower and tractive effort.
The GTEL's were successful but eventually proved too expensive as oil prices rose and the fleet was retired in 1970. As a result, UP looked for other alternatives and continued requesting a 15,000 horsepower, three unit locomotive set.
General Electric came up with what was essentially two U25B's on a single frame in 1963, the U50. The massive road-switcher featured two, 4-cycle model 7FDL16 prime movers which could produce a combined 5,000 horsepower.
A gigantic locomotive in terms of both length and weight it stretched over 83 feet and and registered at 558,000 pounds; similar models built by EMD and Alco at the time featured dimensions closely matching this big U-boat.
With the locomotive's massive size its tractive effort rating was off the charts; 160,000 pounds starting and 139,500 pounds continuous.
Similar to Alco's C855 model, the U50 rode on four B-B trucks (i.e., two axles per truck) giving it a B+B-B+B wheel arrangement.
The model is sometimes referred to as a U50D, which technically is not accurate as it utilized two-axle trucks ("D" would refer to a single, four-axle truck).
GE delivered its first three U50s to Union Pacific in October of 1963; Southern Pacific acquired the next three examples during May and June of the following year.
However, SP was not satisfied with the trio and scrapped the locomotives before 1975. For Union Pacific the carrier wound up with a total of 23 examples.
Interestingly, in the late 1960s GE would again build a high horsepower experimental design for UP known as the U50C, which was slightly different but featured the same horsepower rating.
It was intended to be an improvement over its predecessors but, ironically, wound up suffering far greater issues with onboard fire and other internal issues.
Data Sheet
| Entered Production | 10/1963 (Union Pacific #31) |
| Years Produced | 10/1963 - 6/1964 |
| GE Class | U50 |
| Engine | 7FDL16 (2) |
| Engine Builder | General Electric |
| Horsepower | 5,000 |
| RPM | 1050 |
| Length | 83' 6" |
| Height (Top Of Rail To Top Of Cab) | 15' 10 3/4" |
| Width | 9' 11" |
| Weight | 558,000 Lbs |
| Fuel Capacity | 5,800 Gallons |
| Air Compressor | 3CDC (Westinghouse) |
| Air Brake Schedule | 26L (Westinghouse) |
| Trucks | B-B |
| Truck Type | Swing Bolster, Drop-Side Equalizer (4) |
| Truck Wheelbase | 9' 4" |
| Wheel Size | 40" |
| Traction Motors | 752 (8), GE |
| Traction Generator | GT588, GE |
| Auxiliary Generator | GY27, GE |
| MU (Multiple-Unit) | Yes |
| Dynamic Brakes | Yes |
| Gear Ratio | 74:18 |
| Tractive Effort/Starting | 160,000 Lbs |
| Tractive Effort/Continuous | 139,500 Lbs at 8.5 mph |
| Top Speed | 70 mph |
* These trucks (AAR Type-B) were taken from second generation gas turbine locomotives, #61-75, nicknamed "Verandas."
Production Roster
| Owner | Road Number | Serial Number | Order Number | Completion Date | Quantity |
|---|---|---|---|---|---|
| Union Pacific | 31-33 | 34891-34893 | 2750 | 10/1963 | 3 |
| Southern Pacific | 8500-8502 | 34945-34947 | 2755 | 5/1964-6/1964 | 3 |
| Union Pacific | 34-45 | 35094-35105 | 2760/2761 | 7/1964-9/1964 | 12 |
| Union Pacific | 46-53 | 35644-35651 | 2770 | 5/1965-8/1965 | 8 |
Sources
- Marre, Louis A. Diesel Locomotives: The First 50 Years, A Guide To Diesels Built Before 1972. Milwaukee: Kalmbach Publishing Company, 1995.
- McDonnell, Greg. U-boats. Toronto: Stoddart Publishing, 1994.
- Pinkepank, Jerry A. Diesel Spotter's Guide. Milwaukee: Kalmbach Publishing Company, 1967.
- Solomon, Brian. GE Locomotives: 110 Years Of General Electric Motive Power. St. Paul: MBI Publishing, 2003.
Union Pacific U50 #32 has departed the yard in Marysville, Kansas as she heads east through the city park on August 16, 1969. This segment of main line has since been rerouted around the city to the west, near the Big Blue River. American-Rails.com collection.Final Years
While the U50 did have some mechanical issues perhaps its biggest drawback was simply its weight. At 279 tons the locomotive was very heavy making it extremely hard on the track and roadbed.
Union Pacific continued to operate its fleet until 1973-1974 when the remaining units were put into storage. Here they remained until 1977 when these were either scrapped or traded in to General Electric.
By then, the company had released its updated "Dash 7" series, the C30-7 and B30-7 (which sold more than 1,500 examples combine), and the horsepower race subsided until the 1980's.
Recent Articles
-
Burlington Northern Timetables (May, 1972)
May 21, 26 11:56 PM
Presented here is the Burlington Northern's condensed freight timetables from the May, 1972 edition of the "Official Guide Of The Railways." -
Whiskey Tasting Train Rides (2026)
May 21, 26 11:12 PM
These rides across the United States offer a sensory journey through lush landscapes and historical corridors, often pairing scenic vistas with curated whiskey tastings. -
Father's Day Train Ride Locations (2026)
May 21, 26 10:54 PM
Celebrate dad by train! Several heritage railroads and museums host trips honoring dads. Learn more about which locations offer such excursions. -
The Chessie Safety Express: Steam-Powered Advocacy for Railroad Safety
May 21, 26 10:44 PM
In the fall of 1980, a gleaming Chesapeake & Ohio (C&O) 4-8-4 steam locomotive named No. 614 thundered across the rails of the Chessie System, pulling a colorful consist of passenger cars filled with… -
Frankfort and Cincinnati Railroad: "The Kentucky Midland Route"
May 21, 26 06:08 PM
The Frankfort & Cincinnati was a small shortline located in north-central Kentucky that was known as "The Whiskey Route" for the many distilleries it served. The F&C shutdown in 1985. -
North Carolina 'Whiskey Tasting' Train Rides
May 21, 26 12:43 PM
One of the GSMR's most distinctive special events is Spirits on the Rail, a bourbon-focused dining experience built around curated drinks and a chef-prepared multi-course meal. -
Connecticut 'Whiskey Tasting' Train Rides
May 21, 26 12:42 PM
While the Naugatuck Railroad runs a variety of trips throughout the year, one event has quickly become a “circle it on the calendar” outing for fans of great food and spirited tastings: the BBQ & Bour… -
Kansas "Dinner" Train Rides From Abilene
May 21, 26 12:37 PM
If you’re looking for a heritage railroad that feels authentically Kansas—equal parts prairie scenery, small-town history, and hands-on railroading—the Abilene & Smoky Valley Railroad delivers. -
Vermont "Dinner" Train Rides At Burlington
May 21, 26 12:34 PM
There is one location in Vermont hosting a dedicated dinner train experience at the Green Mountain Railroad. -
New Jersey "Father's Day" Train Rides
May 21, 26 12:24 PM
There are a few locations in New Jersey celebrating dads with a train ride. Learn more about these unique trips here! -
Massachusetts "Father's Day" Train Rides
May 21, 26 12:16 PM
The Cape Cod Central is the one location in the state hosting an event just for dads, a special brunch train. Learn more here! -
Historic Steam Locomotive Heads To Charleston For America250 Exhibit
May 21, 26 11:58 AM
A rare piece of West Virginia industrial history, an 0-4-0F fireless steam locomotive by H.K. Porter in 1945, is being installed near the West Virginia State Capitol Complex in Charleston as part of a… -
Connecticut 'Dinner' Train Rides At Essex
May 20, 26 11:55 AM
Connecticut's rail heritage can be traced back to the industry's earliest days and a few organizations preserve this rich history by offering train rides. The Essex Steam Train also hosts dinner-theme… -
Arkansas 'Dinner 'Train Rides On The A&M
May 20, 26 11:54 AM
If you want a railroad experience that feels equal parts “working short line” and “time machine,” the Arkansas & Missouri Railroad delivers in a way few modern operations can. -
Illinois 'Dinner' Train Rides At The MRM
May 20, 26 11:52 AM
The Monticello Railway Museum (MRM) is one of those places that quietly does a lot: it preserves a sizable collection, maintains its own operating railroad, and—most importantly for visitors—puts hist… -
California 'Murder Mystery' Dinner Train Rides
May 20, 26 11:51 AM
When it comes to experiencing the allure of crime-solving sprinkled with delicious dining, California's murder mystery dinner train rides have carved a niche for themselves among both locals and touri… -
Michigan 'Wine Tasting' Train Rides
May 20, 26 11:50 AM
In this article, we’ll delve into the world of Michigan’s wine tasting train experiences that cater to both wine connoisseurs and railway aficionados. -
Indiana 'Wine Tasting' Train Rides
May 20, 26 11:48 AM
In this article, we'll delve into the experience of wine tasting trains in Indiana, exploring their routes, services, and the rising popularity of this unique adventure. -
Texas & Pacific Railway Timetables (September, 1937)
May 20, 26 11:10 AM
Featured here is the Texas & Pacific's timetables and system map from the September, 1937 edition of the "Official Guide Of The Railways." -
Norfolk Southern Unveils America250 Locomotive Series
May 20, 26 10:30 AM
Norfolk Southern has rolled out a bold new commemorative series to mark America’s 250th anniversary (the nation’s Semiquincentennial in 2026). -
The Nebraska Zephyr: Burlington's Lincoln Service
May 20, 26 09:49 AM
ntroduced in 1947, the Nebraska Zephyr provided fast, stylish daylight service between Chicago, Illinois, and Lincoln, Nebraska (via Omaha), covering 551 miles (887 km) in under 10 hours at an average… -
Colorado & Southern Timetables (March, 1940)
May 19, 26 11:55 PM
Featured here is the Colorado & Southern's timetables from the March, 1940 edition of the "Official Guide Of The Railways." -
New Jersey "Father's Day" Train Rides
May 19, 26 11:59 AM
There are a few locations in New Jersey celebrating dads with a train ride. Learn more about these unique trips here! -
Illinois 'Murder Mystery' Dinner Train Rides
May 19, 26 11:56 AM
Among Illinois's scenic train rides, one of the most unique and captivating experiences is the murder mystery excursion. -
Kentucky 'Dinner Train' Rides From Bardstown
May 19, 26 11:53 AM
The essence of My Old Kentucky Dinner Train is part restaurant, part scenic excursion, and part living piece of Kentucky rail history. -
Vermont 'Murder Mystery' Dinner Train Rides
May 19, 26 11:50 AM
There are currently murder mystery dinner trains offered in Vermont but until recently the Champlain Valley Dinner Train offered such a trip! -
Ohio - Beer Tasting - Train Rides
May 19, 26 11:49 AM
The Ohio Rail Experience's Quincy Sunset Tasting Train is a new offering that pairs an easygoing evening schedule with a signature scenic highlight: a high, dramatic crossing of the Quincy Bridge over… -
Texas 'Beer Tasting' Train Rides
May 19, 26 11:43 AM
Texas State Railroad's “Pints In The Pines” train is one of the most enjoyable ways to experience the line: a vintage evening departure, craft beer samplings, and a catered dinner at the Rusk depot un… -
South Dakota 'Wine Tasting' Train Rides
May 19, 26 11:40 AM
For wine enthusiasts and adventurers alike, South Dakota introduces a novel way to experience its local viticulture: wine tasting aboard the Black Hills Central Railroad. -
New Mexico 'Wine Tasting' Train Rides
May 19, 26 11:33 AM
For oenophiles and adventure seekers alike, wine tasting train rides in New Mexico provide a unique opportunity to explore the region's vineyards in comfort and style. -
Amtrak's First Airo Trainset Arrives in Seattle
May 19, 26 10:01 AM
Amtrak's next-generation Airo passenger trainset has officially arrived in Seattle, marking a major milestone in the railroad's largest fleet overhaul in decades and the start of a new era for travel… -
Maine "Ice Cream" Tasting Train Rides
May 19, 26 09:49 AM
The Maine Narrow Gauge Railroad & Museum’s Ice Cream Train is a family-friendly Friday-night tradition that turns a short rail excursion into a small event. -
TP&W Railway Timetables (January, 1930)
May 18, 26 03:23 PM
Featured here is the Toledo, Peoria & Western Railway's timetables listed in the January, 1930 edition of the "Official Guide Of The Railways." -
CSX SD40-2 8888, "Crazy Eights": The 2001 Runaway Train
May 18, 26 02:02 PM
On May 15, 2001, a single locomotive—CSX SD40-2 No. 8888—began one of the most infamous runaway train incidents in American railroad history. -
North Carolina "Ice Cream Tasting" Train Rides
May 18, 26 01:40 PM
One of the most popular warm-weather offerings at NCTM is the Ice Cream Train, a simple but brilliant concept: pair a relaxing ride with a classic summer treat. -
New York "Ice Cream Tasting" Train Rides
May 18, 26 01:32 PM
While CMRR runs several seasonal excursions, one of the most family-friendly (and, frankly, joyfully simple) offerings is its Ice Cream Express. -
New Mexico 'Murder Mystery' Train Rides
May 18, 26 12:31 PM
Among Sky Railway's most theatrical offerings is “A Murder Mystery,” a 2–2.5 hour immersive production that drops passengers into a stylized whodunit on the rails. -
Michigan 'Murder Mystery' Dinner Train Rides
May 18, 26 12:28 PM
Among the lesser-known treasures of this state are the intriguing murder mystery dinner train rides—a perfect blend of suspense, dining, and scenic exploration. -
Ohio 'Wine Tasting' Train Rides
May 18, 26 12:24 PM
Among the intriguing ways to experience Ohio's splendor is aboard the wine tasting trains that journey through some of Ohio's most picturesque vineyards and wineries. -
Pennsylvania 'Wine Tasting' Train Rides
May 18, 26 12:22 PM
Wine tasting trains are a unique and enchanting way to explore the state’s burgeoning wine scene while enjoying a leisurely ride through picturesque landscapes. -
Minnesota BBQ Tasting Train Rides
May 18, 26 12:10 PM
If you’re looking for a perfect mix of nostalgia, stunning Lake Superior views, and mouthwatering food, the North Shore Scenic Railroad in Duluth, Minnesota, delivers—literally. -
South Carolina BBQ Tasting Train Rides
May 18, 26 12:05 PM
There is only location in the Palmetto State offering a true dinner train experience can be found at the South Carolina Railroad Museum. Learn more here. -
Cotton Belt Railroad Timetables (January, 1930)
May 18, 26 12:00 AM
Featured here is the St. Louis Southwestern Railway's timetables from the January, 1930 edition of the "Official Guide Of The Railways." -
Pere Marquette Timetables (January, 1930)
May 17, 26 11:42 PM
Presented here is the Pere Marquette Railway's timetables from the January, 1930 edition of the "Official Guide Of The Railways." -
Minneapolis & St. Louis Timetables (August, 1952)
May 17, 26 01:19 PM
Featured here is the Minneapolis & St. Louis Railway's timetables featured in the August, 1952 edition of the "Official Guide Of The Railways." -
Virginia 'Murder Mystery' Dinner Train Rides
May 17, 26 01:10 PM
Among the state's railroad attractions, murder mystery dinner trains stand out as a captivating fusion of theatrical entertainment, fine dining, and scenic travel. -
Maryland 'Murder Mystery' Dinner Train Rides
May 17, 26 12:42 PM
Maryland is known for its scenic landscapes, historical landmarks, and vibrant culture, but did you know that it’s also home to some of the most thrilling murder mystery dinner trains? -
Ohio "BBQ Tasting" Train Rides
May 17, 26 11:28 AM
Among the HVSR's most popular special events is the “Starbrick BBQ Ribs and Wings Dinner Train,” a culinary-themed excursion that combines classic barbecue cuisine with a relaxing evening rail journey… -
Florida "BBQ Tasting" Train Rides
May 17, 26 11:24 AM
While Florida does not currently offer any BBQ train rides the Florida Railroad Museum does host a similar event, a campfire experience! -
Wisconsin "BBQ Tasting" Train Rides
May 17, 26 11:18 AM
The Wisconsin Great Northern Railroad will once again welcome passengers aboard its popular Spring BBQ Dinner Train in 2026.
