901 West Pratt St., Baltimore, MD 21223
Detailed Information

B&O No. 25 "William Mason"

Name: William Mason

Railroad of Record: Baltimore & Ohio Railroad

Locomotive Number: B&O No. 25

Type of Locomotive: 4-4-0 American

Class: F

Date Built: 1856

Manufactured By: Mason Machine Works Company

Date Rebuilt: 1927

Locomotive Weight: 28 tons

Driver Diameter: 60 inches

Cylinders: 15 x 22 inches

Tractive Effort: 6,225 lbs

Between 1830 and 1855, the Baltimore & Ohio Railroad (B&O) increased its track mileage from 13 to 411 miles. Locomotive designs improved to meet the increasing demands. The most popular passenger locomotive in the 19th century was the "American" type 4-4-0. In 1856, the B&O ordered two "American" type locomotives from Mason Machine Works in Taunton, Massachusetts, one of which was the No. 25. William Mason, the founder of the Mason Machine Works, introduced the idea of turning out locomotives of beauty as well as utility.

The Civil War was the first American military conflict in which railroads were used for strategic purposes. The use of railroads revolutionized the transportation of troops and supplies, and affected the outcome on the battlefield. The No. 25 was used extensively during the war to transport Union troops and supplies.  B&O President John Garrett understood the financial and political benefits of siding with the Union, despite his personal ties to the South.

The No. 25 was the first B&O locomotive to have a Stephenson link motion valve gear and a round smoke box set on a cylinder saddle. In 1927, the railroad named the locomotive the "William Mason" to honor its builder. The "William Mason" follows the general form of the original No. 25; however it has been rebuilt and modified as an exhibition locomotive.

Throughout the years, the "William Mason" has been featured in many motion pictures, such as "The Swan," "The Great Locomotive Chase" (1956), "Raintree County" (1957), "Wild, Wild West" (1998), "Tuck Everlasting" (2002), and "Gods and Generals" (2003).

The No. 25 was not in the roundhouse at the time of the Roundhouse roof collapse in 2003. The locomotive was last under steam in 2012. In 2017, the locomotive emerged from a multi-year restoration project that returned the locomotive to its original colors and livery. The locomotive is currently on display in the Roundhouse.


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