In 1862, Daniel Gooch designed ten standard gauge 2-2-2 express locomotives for the GWR which got the numbers 157 to 166. Built by Sharp, Stewart & Co., they got the nickname “Sharps”. They had double frames and the inside frame only extended from the cylinders to the front of the firebox, while carrying the load of all moving masses. The Firebox of these locomotives was higher than the boiler barrel. 

As early as in 1879, they were found to be too weak and scrapped. At the same time, ten similar locomotives were built under William Dean and got the same numbers. These now had a flush-topped boiler and a full-length inside frame. With a larger firebox and a somewhat smaller boiler barrel, the power had been increased in comparison to the 1862 locomotives. Also the wheelbase had increased from 16 feet to 17 ft 8 in. It remains unclear if any parts at all were re-used from the older locomotives.

As they were originally thought to be rebuilds of the earlier locomotives, they carried the nickname “Sharpies”. Another name given to the class was “Cobham” from the name of No. 162. A good part of the class survived into the 20th century, having got new boilers at least once. Some even got a Belpaire firebox. Most were withdrawn between 1903 and 1906, with 165 surviving until 1914.