1948 Locomotive Exchange Trials

The 1948 Locomotive Exchange Trials were organised by the newly nationalised British Railways (BR). Locomotives from the former "Big Four" constituent companies (GWR, LMS, LNER, SR) were transferred to and worked on other regions. Officially, these comparisons were to identify the best qualities of the four different schools of thought of locomotive design so that they could be used in the planned BR standard designs. However, the testing had little scientific rigour, and political influence meant that LMS practice was largely followed by the new standard designs regardless. However, the trials were useful publicity for BR to show the unity of the new British Railways. To record the locomotive performances, one of three dynamometer cars were included in the train directly behind the locomotive (with a GWR, LMS and NER version being available).

LMS engines which operated over the Southern Region, where there were no water troughs, were paired with four-axled ex-WD tenders with larger water tanks. These were specially given LMS lettering for the occasion. Similarly, ex-Southern types used elsewhere were paired with ex-LMS tenders with water scoops.

The locomotives used are listed below. (The numbers given are the ones carried at the time, so this is a somewhat curious mixture of old pre-nationalisation numbers, prefixed numbers, and new BR numbers.)