The drivers (sometimes called engineers in recent US narrations) drive and maintain the engines and, along with the fireman, keep the engines in control and provide a voice of reason when an engine is being difficult.
A North Western Railway driver's uniform consists of blue trousers, a black tie, a white shirt with a blue jacket over it, and a blue cap. This dress code is the same for drivers on the Arlesdale Railway. The drivers on the Skarloey Railway wear the same outfits, but in grey instead of blue.
From the eighth to sixteenth seasons of Thomas & Friends, drivers and firemen act almost purely as background characters and are very rarely acknowledged. Engines have on numerous occasions left their jobs without consulting their drivers (if they have any), when in reality, the driver would direct the engine where to go and what to do. But from the seventeenth season onwards, drivers have been seen more often and have worked more realistically.
There have been complaints about the lack of female drivers. Mary Creagh, a Labour Front-bencher, has said it was a negative stereotype, and says it will make women less likely to become train drivers if they are put off in their early years. She also criticised the lack of female characters. HiT Entertainment responded saying there has been a "historical imbalance" but that there will be more female characters/engines in development.