William Paton Reid was apprenticed to the NBR works at Cowlairs in 1879. After serving various positions with the NBR, he was appointed to the position of Locomotive Superintendent in 1903.

Reid continued the practices of his predecessor Holmes, by rebuilding and modernising pre-existing engines. He also introduced super-heating to the NBR, but is probably best known for his powerful D30 "Scott" and D34 "Glen" 4-4-0 classes.

Reid retired in 1919 and received a CBE in 1920. He died in 1932.