Train ferry

A train ferry is a ship (ferry) designed to carry railway vehicles, as well as their cargoes and passengers. Typically, one level of the ship is fitted with railway tracks, and the vessel has a door at the front or rear to give access to the wharves. In the United States, train ferries are sometimes referred to as "car ferries", as distinguished from "auto ferries" used to transport automobiles. The wharf (sometimes called a "slip") has a ramp, and a linkspan or "apron", balanced by weights, that connects the railway proper to the ship, allowing for tidal or seasonal changes in water level. While railway vehicles can be and are shipped on the decks or in the holds of ordinary ships, purpose-built train ferries can be quickly loaded and unloaded by roll-on/roll-off, especially as several vehicles can be loaded or unloaded at once. A train ferry that is a barge is called a car float or rail barge. Some train ferries are considered pure train ferries that only carry rail traffic, whereas others are defined as train/vehicle ferries that also carry vehicles.