They need big, powerful engines to pull them. This steam-powered locomotive carries coal and water in a car called a tender. A fireman shovels coal into the firebox. As the coal burns it heats the water, making steam to power the engine. When the water supply runs low, the engineer stops at a water tower.
Some trains have just a few cars.
Look out the window. There are three busy trains. On an overnight passenger train, travelers relax in private roomettes or watch the sights from the lounge car's dome. Some people sleep in sleeping cars. The steam engine is pulling a cattle car, a side dumper, and a box car.