The Q Stock consisted of various District line trains built from 1923 (G Stock) until the mid-1930s, originally built with manually operated sliding doors. Following conversion to air operated doors, the trains became collectively known as Q Stock. Given that five different types of rolling stock were converted to Q Stock, the resulting hybrid trains looked bizarre - with the older carriages having flat sides and clerestory roofs, whilst the Q38 had flared sides at floor level.