The GE B39-8 (also referred to as the 8-39B) was one of the builder's most powerful four-axle models it ever produced, as well as one of the last. The design, built during the mid-1980s, had lukewarm success although only two railroads ultimately purchased the model as most were bought by a leasing firm. By the time of the model's construction most had lost nearly all interest in four-axle designs in main line freight service for a few reasons; first, six-axle locomotives offered more tractive effort with little loss in speed (another level of redundancy) and second, many still had first and early second generation motive power that could be used without the need of buying new.
General Electric would debut only one other four-axle model after the B39-8, which likewise saw only marginal sales numbers. Manufacturers by this era realized four-axle designs were no longer a profitable business model and stuck solely with six-axle locomotives. Today, most of the original fleet of these locomotives remain in use on a number of different lines.
The GE B39-8 saw a bit of change to the builder's carbody designs. The company continued to carry the standard rectangular design with flush lines (which dated back to the Universal series) and its now classic rear, flared radiator. The "Dash 8s" also have slightly longer nose than earlier models. Perhaps the most noticeable exterior difference with the B39-8 (and all "Dash 8s") was the roughly 10-foot "bulge" directly behind the cab that gave the roof-line a very irregular shape. This new featured simply housed the dynamic brakes. The design continued to use the same classification, which began with the Universal models.
For instance, the "B" referred to the unit having a B-B truck setup (two axles per truck) while the "39" referred to it having 3,900 horsepower. The "8" reference simply meant it was a model of GE's "Dash 8" series. The locomotive used GE's standard 4-cycle, 16-cylinder FDL prime mover featuring its model 752AF traction motors, which by the 1980s had become one of its major marketing features. As a four-axle "Dash 8" locomotive the model could produce 68,500 pounds of starting tractive effort and 68,000 pounds continuous (about the same as the later B40-8W). Of note, the design was one of GE's final cataloged models not to have the later FRA-mandated Safety Cab as a standard feature. The Norfolk Southern, for instance, held out on having its locomotives include this cab until ordered to do so.
Perhaps the most noticeable difference in later B39-8s, from its earlier design and also the B32-8, was the change to the rear radiator air intakes which were now canted (i.e., angled) instead of being flush with the carbody. Nearly all future GE models featured this angular design to their air intakes, which carried on to this day. Production of the design began in early 1984 and only two Class Is purchased the model, AT&SF (3) and Southern Pacific (40). Most, 102 (listed as a B39-8E), were purchased by Locomotive Management Services, which as their name suggests, leases out motive power to railroads. With the one GE demonstrator built overall 146 B39-8s were constructed. Today, numerous regionals and short lines still operate the model, and they can also be found in Canada and South America. Some of the lines that use the locomotive include the Providence & Worcester; Montreal, Maine & Atlantic; Ferrocaril Central Andino (Peru); and the Nashville & Eastern.
For more reading about General Electric diesel locomotives there are a few books written by noted historian Brian Solomon worth mentioning which highlight the history and background of the company. First, is GE Locomotives, a title that provides a thorough history of its locomotive line from the earliest days of building electrics and experimental diesels to the latest models built through the early 2000s. Second, is GE And EMD Locomotives: The Illustrated History, which generally highlights the history of both company's designs. As with virtually all of Mr. Solomon's you can expect well-written titles with large, crisp, and sharp photographs featured throughout.