That year the B&O's General Superintendent of Motive Power & Equipment, George Emerson, wanted to test the practicability of a water-tube firebox. To do so he ordered two 4-8-2s from the Baldwin Locomotive Works; one, numbered 5510 and listed as Class T-1 used a water-tube firebox while another, carrying #5550 and given the designation as Class T-2 used a standard firebox. Unfortunately, Emerson was never able to complete his study but these pair of Mountains remained in regular service on the B&O until the 1950s. The next batch of 4-8-2s were built specifically for high-speed freight service to help keep up with war demands according to David Mainey's Baltimore & Ohio Steam In Color. The locomotives were again constructed at Mt. Clare and the first were outshopped in 1942 using boilers from older Class Q-1 Mikados and P-1 Pacifics; listed as Class T-3 they sported 70-inch drivers with about the same tractive effort as the earlier types.
As Mr. Mainey notes in his book they could have just as easily been used to pull passenger trains given their power and speed. The T-3 class, as was so common on the B&O, was broken down into several subclasses; only one (#5564) had roller bearings on all axles, which was listed as Class T-3a. By contrast, the T-3b's used standard friction bearings and the group of T-3c's had roller bearings on all axles (including the tender) except the main drivers. Finally, there was the curious fleet of T-3t's; these Mountains were distinguished only by their use of tenders, which according to Mr. Mainey's book were of a Vanderbilt design. Most railroads did not subclass their steam locomotives based on the tender used, since they were often swapped and interchanged amongst one another. Altogether, seven examples from the three subclasses ("a," "b," and "c") were equipped with these larger tenders and labeled as Class T-3t.
|Class T||B&O||5500 ("Lord Baltimore"), 5501 ("Philip E. Thomas")||1925-1926||Scrapped, 1953|
|Class T-1||Baldwin||5510||1930||Scrapped, 1951|
|Class T-2||Baldwin||5550||1930||Scrapped, 1952|
|Class T-3||B&O||5555-5563||1942-1943||All Retired By 1960|
|Class T-3a||B&O||5564||1943||Retired By 1960|
|Class T-3b||B&O||5565-5584||1943-1946||All Retired By 1960|
|Class T-3c||B&O||5585-5594||1947-1948||All Retired By 1960|
|Class T-4||Baldwin||5650-5662 (Ex-B&M)||1935||All Retired By 1958|
The entire fleet of T-3's could be found roaming over much of the B&O's system pulling freights on the stiff grades of the Cumberland and Monongah Divisions as well as working further west into the flatter territory of the Akron and Chicago Divisions. The final class of Mountains were the T-4's. These locomotives were handsome machines purchased second-hand from the Boston & Maine in 1947, thirteen in all. With their 73-inch drivers they could also just have easily been used in passenger service although the B&O assigned them to the gentle grades of the Chicago and Akron Divisions where the zipped timed freights incredibly fast through the Midwest's farmlands.
Interestingly, the T-4's were, according to Mr. Mainey's book "...12% heavier, sported larger drivers and cylinders, and had a higher boiler pressure than the T-3's." During November of 1956 the B&O embarked on a complete renumbering of its remaining steam fleet to make room for its growing volume of diesels. The railroad's 4-8-2s were given the 700 series although not all had survived until that time. For instance, only eight examples of the Class T-4's were still in service by then. In any event, the B&O's Mountains survived longer than most of its other main line steamers; the last T-4 was finally scrapped in 1958 while the T-3's could still be found performing limited duties for another year. It's a shame none of the B&O's own 4-8-2s were preserved; they were well-built, fast, and great-looking locomotives that performed any task they were assigned.
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