With the new Lord Nelson class and King Arthur class engines maintaining the majority of express passenger services the operating department issued a requirement for an express passenger locomotive of intermediate power that would be able to operate on lines with severe restrictions such as the Tonbridge to Hastings and Chatham to Ramsgate lines. The initial reaction was to offer a cut down (3 cylindered 4 drivered) Lord Nelson. However this was not found to be practicable since the use of the Nelson's Belpaire firebox within a such a restricted loading gauge would severely impede the forward view from the cab. The solution was to use a shortened King Arthur pattern boiler but retaining the full late series N15/S15 firebox. The boiler operating pressure was 220 psi - 20 psi higher than a King Arthur. The end result more than exceeded expectations since the design proved to be extremely free steaming even with poor grades of coal and with remarkably low internal friction contributing to a tractive effort of 25120 lb - only 200 lb less than a King Arthur. With that power and only 42 tons adhesion weight the class required careful handling when starting from rest!

The first engine emerged from Eastleigh works in mid-March 1930 and was numbered 900. Reflecting the by-now successful public relations policy the class was to be named after Public boarding schools - a traffic flow with which at the start and end of school terms the railway had a long association. 900 was named Eton. It was displayed to the public at Waterloo on 26th March 1930 and not long after taken to Windsor for inspection by boys of that College. This practice was repeated with the relevant school with many of the new introductions.

The first batch of ten, 900-909, was completed at Eastleigh in 1930 and although intended for the eastern section the early locomotives were temporarily assigned to Nine Elms for testing on Waterloo to Salisbury and Bournemouth services. Remarkably no adjustments were found to be necessary during this testing and the qualities of the new design were rapidly becoming apparent. A batch of twenty 910-929 was built at Eastleigh between 1932 and 1934 and then a final ten 930-939 between 1934 and 1935, again at Eastleigh. In the batch of twenty the naming strayed from Public Schools within the Southern sphere but it firmly returned for the final ten.

As with all Maunsell passenger locos the whole class eventually gained smoke deflectors and being primarily an eastern section engine they mostly ran with six wheeled tenders, although in later life two (30912 and 30921) ran with Lord Nelson pattern bogie tenders on the western section. A number of the class were fitted with lemaitre multiple jet blastpipes and chimneys by Bulleid though these had little effect on the already excellent properties. In early BR days they gained mixed-traffic lined black livery which given their distinguished service was not a popular decision. They gained the passenger BR green livery for their later BR days.

Although mostly associated with eastern section services ten were, until electrification, assigned to Fratton for use on Waterloo to Portsmouth services. On this winding and hilly route they provided excellent and spirited service. They were then transferred to Bournemouth Central depot and it is on Waterloo to Bournemouth runs they were able to show repeatedly what they were really capable of. The Schools class was both popular and legendary amongst their crews. First withdrawals were in 1961 and the whole class had been withdrawn indecently early by the end of 1962. Fortunately three members of this distinguished class have been preserved. 30926 Repton has recently been overhauled at the North York Moors Railway, 925 Cheltenham and 928 Stowe are on static display, the former at the National Railway Museum and the latter at the Bluebell Railway. Stowe was purchased from Lord Montagu by the Maunsell Locomotive Society.