Left hand side view. The Douglas DT5 is a dirt track racing bike that was popular in the 1920s and 1930s, particularly in motorcycle speedway.The 500cc horizontally-opposed twin engine set it apart from the many single-cylinder dirt track motorbikes of the time, and the Douglas was dominant in racing in the late 1920s. This particular motorcycle is purported to have been raced by speedway legend Fay Taylour (1904-1983). The Irish-born Taylour was a famous speedway champion in the late 1920s, competing in the UK and Australia. Her performances earnt her the nicknames of 'Flying Fay' and 'the Queen of Speedway'. She switched to car racing in the 1930s and retired in the late 1950s.