The GE U36B

The GE U36B was the last and most powerful 4-axle Universal model the company produced. By the time of its production in the late 1960s GE must have realized that interest for powerful 4-axle road switchers was rapidly declining, as the final sales numbers bore out, with only three roads purchasing the U36B (and only two ultimately used the locomotive in revenue service). With the relative unsuccessful sales numbers of the U36B, GE instead began focusing its efforts on six axle models. Despite the model's poor sales performance it actually became quite famous, particularly among railfans, for its use as power for Amtrak's initial Auto Train that debuted in the early 1970s. Today, despite these units being rather rare there are still a handful in operation; Nashville & Eastern #5772 is originally Seaboard Coast Line #1820 while Transkentucky Transportation operates nine former SCL units.

Seaboard Coast Line U36B #1799 lays over with other power at the Byran Park Shops in Richmond, Virginia on May 13, 1972. The SCL purchased these U-boats between 1970 and 1972.

The GE U36B began production in January, 1969 offering a hefty 3,600 horsepower (utilizing the builder's 4-cycle model FDL16 prime mover), one of the most powerful 4-axle road switchers any locomotive builder ever produced. As GE advanced its locomotive development the U36B, outwardly, began to resemble what would become newer locomotives like the "Dash 7" series, particularly with the flared rear radiator design which first appeared on the U33B. Today, this feature remains a classic GE trademark. In any event, the U36B was the second-to-last Universal series model to enter the company's catalog, as only the U36C was cataloged later in 1971. It was certainly the final four-axle U-boat to enter production as General Electric looked to only focus on six-axle designs, as its late model C-C U-boats sold very well (more than 1,000 were outshopped).

While the flared radiator was a new feature on GE locomotives the U36B mostly still resembled earlier 4-axle road switchers with boxy carbody designs and straightforward engineering that allowed for generally ease of maintenance. As GE's last 4-axle Universal model the U36B sold relatively 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 ordered another 13 (Conrail ordered 4 for use by Auto-Train but these were never delivered). One interesting note about the U36B, and all of GE's four-axle U-boats is that the company never elected to increase the tractive effort rating of the models even as it continued to build more powerful models.

Seaboard U36B #5736 is seen here in Knoxville, Tennessee during the early CSX era on May 23, 1987. The unit began its career as SCL #1784 in 1971.

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 sold the units to various short lines (like those mentioned above). Interestingly, the Transkentucky, which owns the most U36Bs, also operates several units of GE's U28B design, one of the railroads to still employ the locomotive in freight service. In any event, as the remaining U36Bs continue to age some will probably find their way into museum collections for preservation.   Lastly, for more information about the GE U36B and total production numbers of units built please refer to the chart below.

GE U36B Production Roster

Owner Road Number(s) Quantity Date Built
Auto Train Corporation4000-4016171971-1974
Seaboard Coast Line1748-1855, 1776 (2nd)391970-1972


Auto Train Corporation U36B #4002 runs light through Lorton, Virginia during March of 1972. The company purchased 17 examples of the model for use on its service numbered, 4000-4016, between 1971 and 1974.

For more information on the General Electric Universal series consider Mike Schafer’s Vintage Diesel Locomotives, which looks at virtually all of the classic builders and models from Alco PAs to early EMD Geeps. If you’re interested in classic GEs, or diesels in general, this book gives an excellent general history of both.  You may also want to consider the book Evolution of the American Diesel Locomotive by author J. Parker Lamb. As the title implies the book looks at the history and development of the diesel locomotives, covering 200 pages, from its earliest beginnings to the newest designs and models operated today. If you're interested in perhaps purchasing either (or both) of these books please visit the links below which will take you to ordering information through Amazon.com, the trusted online shopping network.

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A History Of The General Electric


Other Four-Axle U-Boat Models



U18B




U25B




U28B




U30B




U33B


Other Six-Axle U-Boat Models



U23C




U25C




U28C




U30C




U33C




U36C


Other U-Boat Models



U50 (Experimental)




U50C (Experimental)