Trains, also known as railway trains and green leather cars, refer to vehicles running on railway tracks, which are usually composed of multiple carriages and are one of the important means of transportation for human modernization. As of 202 1, there are two kinds of ordinary speed trains and emus in China.

The most important machine in human history, called steam locomotive in the early days, has an independent orbit. Railway trains can be divided into freight cars and passenger cars according to their load capacity, and there are also mixed passenger and freight cars, but they will produce a lot of carbon dioxide and pollute the environment.

Trains are a typical example of human transportation using fossil energy. 1804, the world's first steam locomotive was built by British mining technician Drivesk using Watt's steam engine, with a speed of 5 to 6 kilometers per hour.

Because coal or firewood was used as fuel at that time, people called it "train" and it has been used ever since. 1840 On February 22nd, the world's first real train running on the track was designed by Kangwa engineer Charlie Levisik.

1879, Siemens electric company of Germany developed the first electric locomotive.