James Manson was born at Saltcoats in 1845. Having served with the Glasgow & South Western Railway (G&SWR), Manson became the Locomotive Superintendent of the Great North of Scotland Railway (GNSR) in 1883.

Manson's tenure with the GNSR was very short (3 years), but he revolutionised GNSR locomotive design. Old features such as brass domes and open splashers were replaced. He also standardised GNSR design principles to use of inside cylinders.

Although he only produced two designs (LNER J90 and J91) during his GNSR tenure, he also invented the Manson Tablet Exchange Apparatus. This allowed single-line tablets to be exchanged at speeds of upto 50mph. In the interests of maximising safety, Manson refused to patent this invention.

Manson resigned from the GNSR in 1890 when he was appointed to the position of Locomotive Superintendent of the G&SWR. He retired from the G&SWR in 1911 and died on 5th June 1935.