Currently the only operating Pennsylvania Railroad steam locomotive, No. 643 was built by the Altoona Machine Shops as their C/N 2184, Class B4a, in June, 1901. The Pennsy sold her to the Central Iron & Steel Co. in Harrisburg in March of 1917, where she ran until 1959 as their No. 5. The 643's signature Belpaire boiler was replaced by a radial-stay type boiler from the H.K. Porter Co. in 1945. After retirement, the engine was acquired by the Williams Grove Historical Steam Engine Association, and operates today on occasion at Williams Grove Park. See the WGHSEA web site for further info. Also seen in the photo is the WGHSEA's Whitcomb mechanical diesel switcher No. 8.
