Baltimore and Ohio Railroad locomotives

On the Baltimore and Ohio Railroad, locomotives were always considered of great importance, and the railroad was involved in many experiments and innovations.

The name Tom Thumb is forever associated with the B&O, as the first steam locomotive built in the United States for an American railroad. It was built strictly as a demonstrator, but it was succeeded by a series of similar locomotives (the "Grasshoppers" and the "Crabs") designed by Ross Winans, the first head of motive power on the railroad. Early B&O designs were quite unlike those used on other roads, due to in-house design and the emphasis of pulling power. 4-2-0 locomotives from Norris (represented by the "Lafayette" reproduction in the B&O museum's collection) were the anomaly on a railroad which was already building eight-coupled (0-8-0) locomotives well before the Civil War. By the beginning of the war, new power on the railroad had become more conventional, though many of the older, unconventional designs remained.

Up until 1884 locomotive numbers were reused when locomotives were retired; numbers were not allocated sequentially (unless lower numbers were used up). In 1884, in order to reduce confusion, all locomotives were renumbered to group like locomotives together, and thereafter numbers were retired along with the locomotive to which they referred.

John W. Garrett's desire to have a line to New York led to the construction of the Baltimore Belt Line in order to bring the railroad across Baltimore. The most important feature of this was the Howard Street Tunnel, which began at Camden Station and headed north to Mount Royal Station. Objections to use of steam led, in 1895, to the first main line electrification in North America. Trains in one direction were pulled through the tunnel, by a series of electric locomotives that lasted until the end of steam; in the other direction, the train simply drifted down the slope. Dieselization made the electrification unnecessary and it was discontinued in 1952.

Another innovation was the introduction of Mallet locomotives. Economies in haulage could be achieved by reducing the number of locomotives and trains needed, so ever more powerful locomotives were always sought. In 1900 #2400, a 0-6-6-0 design, was introduced, and quickly became known as "Old Maude" after a mule in a cartoon. "Old Maude" was renumbered to #7000 in 1915, and it boasted an impressive 71,500 pound tractive effort and was a great success at a Maximum speed of only 21 mph. It was the first Mallet in North America. Mallets were built in large numbers for the B&O, culminating in the huge EM-1 2-8-8-4.

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