I'm assuming the questioner is American so using "engineer" as = "driver" in the UK.
A thorough knowledge of the machine itself - how it works etc., how to prepare, fire and drive it at its most efficient for the required speeds, train weights & track conditions.
A thorough knowledge of the particular railway's operating & safety rules & procedures; and of its route.
Good physical health including good eyesight.
Anything else? Oh yes - knowing the difference between a "train" and a "locomotive" (or "engine") would be a good start!
Trevithick, a british engineer built the first steam locomotive in 1804
to take on water
A train that runs on steam. But first you need the coal and fire and shovel.
Edward Pease built the first public railway that used a steam locomotive, the Stockton & Darlington Railway. The chief engineer for this line and its train was George Stephenson, a self-taught engineer and the accepted "founder" of modern railways.
Engineer operates the engine of a train. (the driver) Conductor is the Boss of the train.
Steam train translates as Dampflokomotive.
The first successful use of steam to drive a train occurred in 1804, when the British engineer Richard Trevithick built and operated the Penydarren locomotive. This steam-powered locomotive pulled a train along a track in South Wales, demonstrating the feasibility of steam power for rail transport. However, it was George Stephenson's locomotive, the Locomotion No. 1, built in 1825 for the Stockton and Darlington Railway, that marked the beginning of commercial steam railway use.
A railroad engineer, locomotive engineer, train operator or engine driver
The first steam train was called the rocket.
A Steam Train Passes was created in 1974.
steam train
A railroad engineer, locomotive engineer, train operator or engine driver