Notes: Construction of an earlier bridge, designed by Sir Thomas Bouch, got as far as the laying of the foundation stone, but on Bouch's death the project was transfered over to Sir John Fowler and Sir Benjamin Baker, and was built by Sir William Arrol's company between 1883 and 1890.

The bridge is still regarded as an engineering marvel. It is 2.5 km (1.5 miles) in length, and the double track is elevated 46 m (approx. 150 ft) above high tide. It consists of two main spans of 1,710 ft (520 m), two side spans of 675 ft, 15 approach spans of 168 ft (51 m), and five of 25 ft (7.6 m).[3] Each main span comprises two 680 ft (210 m) cantilever arms supporting a central 350 ft (110 m) span girder bridge). The three great four-tower cantilever structures are 340 ft (104 m) tall, each 70 ft (21 m) diameter.