The outcome, in 1870 was a locomotive with driving wheels, designed specifically for high speed expresses between York and London. The norm in those days was inside cylinders. Not only were there frequent failures of the cranked axle shafts, with such large driving wheels, they would have set the boiler too high. He therefore used outside cylinders with a four-wheeled bogie for lateral stability at the front end. According to Hamilton Ellis's description entitled 'Pat Stirling's masterpiece,' the design was a version of a 2-2-2 designed by Stirling for the Glasgow and South Western Railway, 'considerably enlarged, and provided with a leading bogie.'