The locomotive known as "Joyce" was Manufactured by the Sentinel Wagon Works at Shrewsbury in 1927 under works number 7109. Weighing 28 tons, she is a balanced, double-engined, and single-geared, industrial steam locomotive with a pair of transverse engines at the front and a vertical water-tube boiler at the rear in the cab. It uses both gears and chains to transfer the drive to the axles. Unlike later Sentinel locomotives, it has only a single gear ratio.
No. 7109 was bought in 1928 and delivered new for use in Croydon Gasworks where it had operated for 32 years until it was retired in 1960. It was named "Joyce" after the daughter of Mr Sandeman, the chairman of the works company.
In 1968 it was moved for a time to Bressingham before being moved to Steamtown at Carnforth in 1986.
It arrived at Midsomer Norton Station near Radstock in 2004 and its restoration to full working order was led by its owner Andy Chapman with the aid of members of the Somerset & Dorset Railway Heritage Trust (S&DRHT).
In June 2022 the Somerset & Dorset Railway Heritage Trust started an appeal to purchase the locomotive from the current owner Andy Chapman. The aim is to raise enough funds to retain the locomotive at Midsomer Norton as it is almost identical to two engines purchased by the Somerset & Dorset Joint Railway Company for use at Radstock.