A train ferry is a ship designed to carry railway vehicles. Typically, one level of the ship is fitted with railway tracks, and the vessel has a door at the front and/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, linkspan or “apron”, balanced by weights, that connects the railway proper to the ship, allowing for the water level to rise and fall with the tides. For an example of a specialized slip to receive railcars see ferry slip.
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.
In 1833 the Monkland and Kirkintilloch Railway operated a wagon ferry on the Forth and Clyde Canal in Scotland. In April 1836 the first railroad car ferry in the U.S., the Susquehanna entered service on the Susquehanna River between Havre de Grace and Perryville, Maryland. The first ‘modern’ design of ferry, the Leviathan, was designed in 1849 by Thomas Grainger for the Edinburgh, Perth and Dundee Railway to cross the Firth of Forth between Granton and Burntisland. The service commenced on 3 February 1850. It was intended as a temporary measure until the railway could build a bridge, but this was not opened until 1890, its construction delayed in part by repercussions from the catastrophic failure of Thomas Bouch’s Tay Rail Bridge; Bouch designed the ferry loading mechanism.
The largest train ferry ever built was the Contra Costa, serving the mainline of the Central Pacific (later assumed by its affiliate, the Southern Pacific) at the Carquinez Strait in the San Francisco Bay Area in California. Its sister ship, the Solano (built before the Contra Costa) was the second largest train ferry ever built.