The rolling stock, the items that move on a model railroad are:
Locomotives: they pull the cars and trains on the track.
Freight: goods are moved in freight wagons. These have evolved significantly over the years due to changes in standards and safety, manual vs. automatic loading as well as in the modern ear handing containers. As containers are a post-1960 development, I will not be using them on my layout.
Passenger: these are cars designed to move people between stations. Development of these has also occurred for safety and creature comfort reasons.
Next: Control equipment