A train driver is a person who operates a train, railcar, or other rail transport vehicle. The driver is in charge of and is responsible for the mechanical operation of the train, train speed, and all of the train handling (also known as brake handling). Train drivers must follow certain guidelines for driving a train safely.

For many American railroads, the following career progression is typical: assistant conductor (brakeman), train conductor, and finally the engineer. For many years the fireman was next in line to be an engineer, but that classification has been eliminated. In the US, engineers are required to be certified and must then be re-certified every two to three years.

The traditional career progression in the United Kingdom (for steam locomotives) was engine cleaner, passed engine cleaner (i.e. the employee has passed the assessment for fireman), fireman, passed fireman (i.e. passed assessment for driver), and driver. Michael Reynolds, locomotive inspector of the London, Brighton and South Coast Railway proposed a system of locomotive driving certificates, as a stimulus of improvement of service and competency. However, no such system was ever universally adopted by the railways of the UK.

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