GE "U36B" Locomotives: Specs, Roster, History

Last revised: January 2, 2025

The U36B was the final four-axle variant General Electric cataloged as part of its Universal line. It was also the powerful B-B road-switcher any manufacturer ever offered, boasting an impressive 3,600 horsepower.

From a historical perspective, GE's early 7FDL prime mover is often underappreciated for its ruggedness and pure horsepower capability.

The U36B was a compact design at just over 60 feet in length, yet offered 600 more horsepower than any other model.

By comparison, Alco offered its C636 and Electro-Motive its SD45; both of which could also produce 3,600 horsepower. However, these models were C-C variants (six axles) and considerably longer (the C636 was nearly 70 feet in length and the SD45 over 65 feet).

From a sales perspective, the U36B was not a success. However, its numbers were aided by Seaboard Coast Line's order, which totaled 108 examples of the 125 sold.

By the 1970s, railroads were well aware of the advantages that six-motored, high-horsepower locomotives offered. As a result, comparative four-axle models saw increasingly fewer orders.

Interestingly, the U36B did earn some distinction among train enthusiasts as the type chosen to power the all-new Auto Train of 1971.

The service was a privately-funded and managed operation. Its trademark was allowing passengers to take their automobile with them when traveling from Virginia to Florida.

The idea was initially successful although the Auto Train later foundered. It was subsequently retained by Amtrak and remains a popular service today.

Photos

Seaboard Coast Line U36B #1776, in its Bicentennial colors, is seen here leading a long freight through Raleigh, North Carolina during the summer of 1971. Warren Calloway photo.

History

The U36B was a continuation of the earlier U33B with the first unit, Seaboard Coast Line #1748, rolling out of Erie, Pennsylvania in May, 1970.

GE made no fanfare of the upgraded model, which first began testing in October, 1967 as upgraded U33B variants. according to Greg McDonnell's book, "U-boats."

Interestingly, neither did the largest buyer of the model, Seaboard Coast Line. The railroad numbering series for the U36B was simply a continuation of the U33B line.

As GE advanced its locomotive development, the U36B outwardly carried many of the same features of the first "Dash 7" designs.

Most notable was the rear flared radiator which had first appeared on the U33B to handle the increased horsepower. Today, this feature remains a classic GE trademark.

Reception

As GE's last 4-axle U-boat, the U36B sold poorly with just 125 units built by the time production had ended in December, 1974.

The Seaboard Coast Line purchased the most, 108, and the Auto-Train Corporation originally ordered another 17. However, in an interesting twist, the company went bankrupt before the final four units were delivered.

As a result, what would have became Auto Train #4013-4016 sat on GE property for two years before Conrail expressed interest in the quartet in 1976.

The units became Conrail #2971-2974 and were delivered to the new upstart in September, 1976. These locomotives carried particular noteworthiness as the first new power on the Conrail system.

The Seaboard Coast Line's 103 models remained in use through the CSX Transportation merger of the 1980s. The company had mostly retired the fleet by the early 1990s and subsequently sold the units to various short lines.

Lastly, for more information about the U36B, data sheet information, and production totals please refer to the charts below.

Data Sheet and Specifications

Entered Production	5/1970 (Seaboard Coast Line #1748)
Years Produced	5/1970 - 12/1974
GE Class	U36B
Engine	7FDL16 (16 cylinder)
Engine Builder	General Electric
Horsepower	3600
RPM	1050
Length	60' 2"
Height (Top Of Rail To Top Of Cab)	14' 9"
Width	9' 11"
Weight	254,800 Lbs
Fuel Capacity	3,000 Gallons
Air Compressor	3CDC (Westinghouse)
Air Brake Schedule	26NL (Westinghouse)
Trucks	B-B
Truck Type	Swing Bolster, Drop-Side Equalizer (GSC) or Floating Bolster FB2 (GE)
Truck Wheelbase	9' 4"
Wheel Size	40"
Traction Motors	752 (4), GE
Traction Alternator	GTA-11AC, GE
Auxiliary Generator	GY27, GE
MU (Multiple-Unit)	Yes
Dynamic Brakes	Optional
Gear Ratio	74:18
Tractive Effort (Starting)	70,000 Lbs
Tractive Effort (Continuous)	64,000 Lbs at 10.7 mph
Top Speed	70 mph

Production Roster

Owner	Road Number	Serial Number	Order Number	Completion Date	Quantity
Seaboard Coast Line	1748-1777	37411-37440	1000	5/1970-8/1970	30
Seaboard Coast Line	1813**	37439	1000	8/1970	1
Seaboard Coast Line	1778-1812	37774-37808	1005	3/1971-8/1971	35
Seaboard Coast Line	1776 (2nd)***	37999	1005	6/1971	1
Auto Train	4000-4004*	38031-38035	1009	11/1971	5
Seaboard Coast Line	1814-1834	38036-38056	1008	9/1971-12/1971	21
Seaboard Coast Line	1835-1855	38278-38298	1012	1/1972-3/1972	21
Auto Train	4005-4009*	38744-38748	1484	12/1972	5
Auto Train	4010-4012*	39845-39847	1434	5/1974	3
Auto Train	4013-4016****	40064-40067	1434	12/1974	4
Conrail	2971-2974*****	40064-40067	1434	12/1974	4

* Equipped with Blomberg trucks.

** Original #1776.

*** Delivered in June, 1971 wearing a red, white and blue Bicentennial livery.

**** Built but never delivered.

***** Former Auto Train #4013-4016, acquired after the company went bankrupt. These four units were Conrail's first new diesels.

All Seaboard Coast Line U36B's were equipped with Blomberg trucks.

Sources

Foster, Gerald. A Field Guide To Trains. New York: Houghton Mifflin, 1996.

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.

A nice cab view of Seaboard Coast Line U36B #1776, wearing its Bicentennial colors, in Raleigh, North Carolina in 1971. Warren Calloway photo.

Today, at least one U36B is preserved, former Seaboard Coast Line #1776 (2nd) that originally wore Bicentennial colors upon its delivery in 1971. Today it resides at the Lake Shore Railway Historical Society.

The unit had spent a great deal of time at the Massachusetts Call Volunteer Firefighters Association following retirement from CSX.

During this time the museum states that it served as "a rolling education/training unit for emergency services and police personnel across the eastern United States."