The basic layout of the class was influenced by the existing ‘’Lord Nelson’’ class 4-6-0 design, but the use of the round topped firebox enabled Maunsell to design the cab's curved profile to fit the gauge restrictions of the Hastings line while allowing adequate forward visibility. The short frame length of the 4-4-0 locomotive also meant very little overhang on the line's tight curves. To maintain the high power rating required for express passenger engines, Maunsell opted for a three-cylinder design. In terms of
tractive effort, the class was the most powerful 4-4-0 ever built in Britain, and were the only 4-4-0 type to be given the power classification of 5P by
British Railways. They were well liked by crews. They also had a higher tractive effort than the nominally more powerful King Arthur class 4-6-0s, but at the cost of high axle-loading: . The
permanent way on the Hastings line therefore had to be upgraded during 1929 and 1930 to accept the new locomotive. Permission was granted for the first batch of fifteen locomotives in March 1928, but this was reduced to ten when it became apparent that they would not immediately be able to operate on the Hastings route. Production delays at
Eastleigh railway works meant that they were not delivered until between March and July 1930. Once the original batch had proved their worth and had been well received by the crews a further twenty locomotives were ordered in March 1931 for delivery between December 1932 and March 1934. A third batch of twenty were ordered from Eastleigh in March 1932 after the completion of the previous order, but this was subsequently reduced to ten locomotives because of the continuing
trade depression. The final locomotive in the class was delivered in July 1935.
Naming the locomotives The Southern Railway continued its 1923 naming policy for express passenger locomotives with this class. As several
public schools were located on the Southern Railway network, the locomotives were named after them. This was another marketing success for both railway and schools concerned, continuing in the tradition of the N15
King Arthur and
Lord Nelson classes. Where possible, the Southern sent the newly constructed locomotive to a station near the school after which it was named for its official naming ceremony, when pupils were allowed to view the cab of "their" engine. Extension of the class meant that names from "foreign" schools outside the Southern Railway catchment area were used, including
Rugby and
Malvern.
Modifications The class performed well from the outset, but there were a number of minor modifications over the years. The first ten were built without
smoke deflectors, but these were added from August 1931, and the remaining thirty were fitted with them from new. Following the successful introduction of the
Lemaître multiple jet
blastpipes on to the
Lord Nelson class, Maunsell's successor
Oliver Bulleid began to fit them to the
Schools class. However no discernible improvement to draughting was experienced, and only twenty examples were so modified, the most obvious change in their appearance being the large diameter chimney. ==Operational use==