Multiple-Unit Trains were trains without a locomotive. They were more efficient than locomotive trains.
(Note: The background section of this page uses most of the same words as Terra Futura's page on electric locomotives to save time.)
The first railways used horse-drawn wagons to ferry passengers. This was an ancient Greek idea adopted in Germany in the 1500s. The German wagonways were called tramways. Soon, they spread to other parts of Europe. At first, the rails were made of wood. In 1767, the rails started being made of cast iron. There was one problem with cast iron. It broke. In 1820, wrought iron replaced cast iron. Then, in the 1860s, the discovery of the Bessemer process allowed steel rails to be used. All of this iron replacement coincided with the development of the steam locomotive.
The first steam locomotive appeared in Britain in 1804. The inventor was Richard Trevithick of Cornwall. The earliest railways to use steam engines were in Britain and its colonies. The earliest in 1825 was the Stockton and Darlington Railway in North East England. As steam engines, they spread to France and, in a limited supply, to Russia. he steam locomotive was introduced to the United States in 1830. As the railways expanded, the economies of many different nations grew. As the 20th century began, steam locomotives began to be replaced by more advanced locomotives. The last railway to get rid of steam engines was British Railways in 1968. However, in the early 21st century, a few new steam engines were brought into service in Britain. One replacement for steam power was the diesel locomotive.
Diesel locomotives were more efficient than steam locomotives by far. When they were adapted to use in trains in 1896, diesel engines started replacing steam engines. The first country to do this was the United States. Soon, all the countries in Europe followed suit. Diesel engines were cheaper than steam engines. Therefore, they could go for longer than a steam engine without an overhaul. That is why they replaced steam locomotives. The last railway to replace steam engines with diesel engines was the UK. Diesel locomotives would continue to be used into the early 21st century. By then, however, some railways had replaced diesel locomotives with electric locomotives.
The concept of electric locomotives dated back to 1837. However, it was not until the late 19th century that electric locomotives started becoming common. They really took off in the early 20th century on urban lines. In the first half of the 20th century, urban lines were commonplace. However, the rise of the car rendered them mostly obsolete. In the late 20th century, electric light rail lines were connecting every major city to its suburbs. The most famous was the Dallas Area Rapid Transit (DART). At the same time, mainstream rail lines were being electrified. By 2030, all railways were electric. Electric engines did their job well. In most cases, however, locomotives were being replaced by multiple-unit trains.
Tech Level: 9-12
Multiple-unit trains were not new in second half of the 20th century. They had been around since the 1890s. It was only during the second half of the 21st century that multiple-unit trains became common. They were more efficient than locomotive trains in terms of energy. Thus, by the end of the 20th century, multiple-units were used in most passenger trains. Some of them were high-speed trains.