The locomotive was bought new by Babcock & Wilcox Ltd., boilermakers, and worked for its first 20 years at their Renfrew Works. It was transferred to Babcock's tube mill at Dumbarton in 1946, where it was out of use by 1969. Transferred back to Renfrew in 1972, it was overhauled by the company's engineering apprentices, returned to working order and named after the company Chairman. When the railway system at Renfrew Works ceased to be used, it was donated by the company to SRPS.
The locomotive is not currently in working order, and does not carry its name. It has an important job to do as 'Percy' for the many young fans who come to admire it on 'Days Out with Thomas'.