Going Railroading

Many of those in the narrow gauge engine service started as fireman while in their early 20s. The youngest who I have found was Salida engineer Charles D. Wilson, who was 18 when he first marked up as a fireman.
Alamosa engineer Roy Turney was 19. One of the older engineers to start in the engine service was Salida's Zed Scott, who was 32 when he started in 1923.
Checking seniority dates against birthdays has its drawbacks. Some people get hired, leave for one reason or another then come back.
Back to Wilson: worked for 53 years, retiring in 1961. He was the senior engineer when the Poncha Pass and Marshall Pass lines quit and the Monarch Pass line was standard gauged. According to Alamosa engineer Bob Morgan, the Salida men also ran the line from Alamosa to Hooper, even though it was cut off from the rest of the Salida trackage.