Neptune's Staircase Train Ferry

The Neptune's Staircase Train Ferry was used transport Silver Lady beneath the two swing bridges at Banavie. The ferry was lowered into the water by means of a derrick.

Real World Equivalent
Train Ferries are ships specifically designed to carry railway vehicles, usually using a roll-on roll-off mechanism. The earliest example of a modern train ferry was built in 1849 for the Edinburgh, Leith and Newhaven Railway, allowing the company to carry trains across the Firth of Forth. The ferry was superseded in 1890 by the construction of the Forth Rail Bridge.

In the United Kingdom, there are currently no operational train ferries. However working examples exist in a variety of countries including Canada, China, Denmark, Germany, Sweden and the United States.