The Transporter Bridge provides an alternative method of solving the conflict to transporting traffic across the river while at the same time allowing shipping movements upstream and downstream. It is particularly applicable where the span is very long and other methods are considered too difficult to construct. While the first transporter was constructed by Albert del Palacio in Billiao, it is the French Engineer Ferdinand Arnodin who patented the idea in 1887, and was involved in most of them that were built.
The transport consists of a tall tower on each river bank with a connecting beam located at a height to give clearance to the tallest ship. A platform or gondola is suspended by cables from beam. This gondola is level with the approach road so that traffic may drive on to it. The gondola then moves along the beam, crossing the river at the same time, until it reaches the other river bank where the traffic drives off the gondola. The main disadvantage of this type is the limited carrying capacity and the high maintenance costs.
Fewer than two dozen transporter bridges were ever built with just a handful still in use today; Vizcaya Bridge, Spain (1893), Rochefort-Martreu Bridge, France (1900), Newport Transporter Bridge (1906) and Middlesborough Transporter Bridge (1911), both in the United Kingdom and Rendsburg High Bridge, Germany (1913) which is the only known combined railway/transporter bridge.
The largest of these is the Newport Transporter Bridge with a span of 196 m (645 ft) and a shipping clearance of 57 m (187 ft.).