The son of NNRy engine hostler George Cahill, Arthur was born in Raton, New Mexico on October 3, 1903. George moved the family to Ely around 1915. Arthur would attend the Ely public schools before being hired onto the NNRy as a callboy at the age of 16 in 1920. He married Alice Perrier and together they would have three children.

Call boys for the railroad were responsible for alerting crews to their call time for train service in the days before everyone had a phone in their homes. They needed to know the crews and their habits in order to give them plenty of notice for the upcoming work.

A year after hiring on with the railroad, Arthur became a machinist apprentice and later a full machinist. While mostly working in the shops, he was listed as working in the ore delivery service for a brief time period.

In 1959, Arthur was promoted to the position of Master Mechanic following the retirement of George F. Lake. He served in that position until his sudden death on February 16, 1964 due to an illness. At the time of his death he was the most senior employee in years of service to the railroad.

Through his tenure at the railroad, he say the transition from steam to diesel power and the end of passenger service. As a machinist he worked with aging equipment,much of which would be replaced with new machines during his time as Master Mechanic.

The car repair shop, also known as the RIP building, has a plaque dedicated to his long years of service to the railroad.