You can become a train driver in vocational schools now. But those who have to take the exam can become a train driver only if they pass the exam.
The "Driving License" of railway train drivers is subject to unified management across the country. The permitted driving types are divided into three categories: A, B, and C according to the type of locomotive and the transportation tasks performed. That is, Category A is allowed to drive. Diesel, electric locomotives and EMUs; Category B is allowed to drive diesel locomotives and EMUs; Category C is allowed to drive electric locomotives and EMUs.
Extended information
The driver is the person who masters the "machine". Machines appeared in human society after Watt invented the steam engine. Since then, the word driver has appeared. Extending from this meaning, all people in charge of machines can be called drivers.
Later, with the emergence of trains and automobiles, more "drivers" appeared on these means of transportation. Later, the reason why "driver" fully inherited the word "driver" is probably because the profession of "driver" was more frequently called "driver". Gradually, it became a full-time title for drivers.
Reference materials? Driver-Baidu Encyclopedia