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The B&O Museum in Baltimore, MD held their Steam Days event on the weekend of October 4-5, 2008. Two of the museum’s steam engines were fired up for the occasion, which were their 0-4-0T No. 4, and ex-B&O 4-4-0 No. 25, the "William Mason". Excursion trains powered by No. 4 were operated between the museum and their connection with CSX at Mount Clare Junction, 1.5 mile west of the museum. The "William Mason" ran light on the museum’s track ahead of each excursion run so passengers could watch this historic engine in action on an adjacent passing track. Engine No. 4 was built by the H. K. Porter Company in 1950, and was one of the last steam engines built in the U.S. It was used at St. Elizabeth’s Hospital in southeast Washington D.C. for over 20 years to haul carloads of coal from the B&O Railroad connection to their coal-fired power plant before being retired. The "William Mason" was built in 1856 in Taunton, Massachusetts by the Mason Machine Works, and it is the oldest operating steam locomotive in the U.S. It was originally built as a wood burner, however the B&O converted it to burn coal a few months after it was purchased. The B&O Museum converted it back to a wood burner. In this photo Sunday’s noon train, powered by 0-4-0T No. 4, is stopped on the main while the "William Mason" steams by on the adjacent passing siding for passengers to observe.