Most firemen started their careers as cleaners. They attended to the steam locomotive's fire boxes and smoke boxes before the start and at the end of the working day. This was an informal apprenticeship for the ultimate role of driver. Through working on the engines the cleaners became familiar with all their working parts. The next step on the locomotive career ladder was fireman. Stoking and maintaining the fire which generated the heat necessary to create steam was the obvious part of their job as was ensuring the water supply was adequate to produce steam in adequate amounts for the journey in hand. However, as signalling became more complex the fireman became a crucial set of extra eyes for the driver. No more simply stoking and making tea. Firemen were required to keep an eye on the signals and act as a complete back-up for the driver. Fireman were also trained to be capable of stepping into the driver role in case of emergency.