In the first book of the series Jimmy is moved out of the factory where he was made in 1926 to work as the engine on the passenger trains between the town of Ardnochan near Glasgow to the local port where the ferry leaves from to travel to Ireland.

Normally Jimmy has two carriages to pull but has four carriages when the ferry has arrived. The line to Ardnochan is steep and only the best, strongest and safe small engines can be used.

After a difficult first day Jimmy is succesful and stays on the branch line for another 40 years.