For every type of train, there are several basic, similar parts. Each part of the train assists the other parts of the train; each works in tandem with the rest. If you want to learn how a train works start by learning each individual part of a train and what it does.
Bogeys are the trucks on the bottom of train cars, much like the trucks on a bottom of a skateboard or the bottom of roller skates. The bogeys contain the wheels--attached to an axle and a wheel set--that keep the train moving along the track. The majority of bogeys are rigid, though some of them are flexible, or steerable. Engineers invented steerable bogeys to allow trains better maneuverability on curved tracks.
There are many different types of rail cars. Passenger cars, built to combine efficiency and comfort, make up the majority of commuter trains; passengers can sleep, sit and eat and drink in these passenger cars. Hoppers move top-loaded materials like grain, corn, sand, coal or any other product that is too small to put into a boxcar. Boxcars move things that need to be side loaded for the maximum utilisation of space, such as boxes or shipping containers. Many people are familiar with the boxcar, which is a plain or painted metal rectangle, sometimes stacked in twos.
On older trains, the conductor would guide the train from the last car, called the caboose, by leaning out of the window and watching the tracks; she made sure that there were no blockages or guided the train when the railroad forked. Cooks or staff sometimes resided in the caboose. Most newer trains no longer pull a caboose, as modern rules do not allow for the use of the caboose as a conductor's office. The reason for this is that the speeds that trains now travel call for a better conductor viewpoint from the front of the train.