William Aston, who had been chief engineer of the Cambrian since 1882, had already revised the six Beaconsfield class locomotives to cope with the increased train weights and tighter schedules. It was all about the express trains that transported holidaymakers to the tourist areas of Wales. From 1893, class 61 locomotives were procured to meet the increased requirements in this area, which represented an extension of the Beaconsfield class.

Compared to their predecessors, the locomotives received larger cylinders, larger drivers and a new boiler with 20 psi higher pressure and a larger firebox with larger grate. In the years 1893 to 1895, 16 were made by Sharp, Stewart & Co., which received the numbers 61 to 72 and 81 to 84. Five more followed in 1897 by Robert Stephenson & Co., numbered 32, 47, 11, 85 and 86. Number 19 was special as it was only built in 1901 in the Cambrian Railway's own workshops in Oswestry.