Ferry slip

Tug-propelled Dartmouth ferry barge with integral ramp at each end

A ferry slip is a specialized

docking facility that receives a ferryboat or train ferry. A similar structure called a barge slip receives a barge or car float that is used to carry wheeled vehicles

across a body of water.

Often a ferry intended for motor vehicle transport will carry its own

tracks

for them.

In some parts of the world, the structures are also known as linkspans and transfer bridges.

San Francisco example

In the example shown below, a tugboat was positioned on the left side of the barge (our right in the apron view), pulling it with a stout rope called a springline. Nearly identical structures were used around San Francisco Bay. Unlike the electric motor drive used here and elsewhere, the Point Richmond ferry slip used water tanks as a portion of the counterweight, with the amount of water (provided by gravity from a local creek) regulated to move the apron up or down by admitting or draining water from the tanks.

**Railcar barge slip**

**Left:** Headworks to lift and lower apron. **Right:** Apron for railcars.

Here, three tracks are provided for loading the barge. On the barge the three tracks are spread to allow clearance for the freight cars. The slip consists of pilings and guide boards to accurately position the barge relative to the apron. Once the barge is located properly, links are lowered from the apron to engage hooks on the barge, locking the linkspan and barge together.

While the apron shown could bear the weight of a locomotive, it could not withstand the traction, so a string of flatcars was used to link the locomotive to a short string of railcars, which were then moved on or off of the barge. If a locomotive was to be moved (a rare event), it would be moved by another locomotive using the same method. The auxiliary track to the left of the headworks was for storage of the flatcar string.