The railway profession was a hierarchy. One had to start as an engine cleaner and work one's way up to the position of stoker. One could then became a goods train driver before being allowed to carry passengers. The chain of promotions required effort. Stokers had to be extremely fit and skillful to be able to keep shoveling coal into the firebox of a railway engine from the swaying open engine platform.
Engine drivers have equal demands on their bodies.
They had to pass a medical exam each year as the safety of the train, crew and passengers depended on the engine driver's alertness. William was an engine driver when his daughter, Jessie, was born in 1864. He was back to the lower position of railway stoker when his son, William, was born in 1866. He had returned to being an engine driver as of the birth of daughter, Agnes, in 1868 but was a labourer in Banbridge at the birth of his son, Thomas, in 1871. He became an engine driver again only when his son, Samuel, was born in 1873.