Construction

To permit operation along 29 km of route, it has been necessary to lay some 60 km of track bed with approximately 120 km of rail and similar length of contact wire to carry power supplies. More than 30 new structures have been built.

The Track

Each track in the highway sits on a concrete bed 2.20 metres wide, with two channels measuring 170 x 165 mm for the rails.  The rails have concrete blocks positioned against the webs to increase lateral strength and are secured in their channels by a special, solvent-free polyurethane adhesive which incorporates cork called an "elastomer".  The overall effect is an inherently "springy" system which reduces noise and vibration, and electrically insulates the trams from surrounding carriageway.

The surface treatment of the track bed varies to match the specific surrounding environment.  Large sections of segregated route are ballasted track filled with gravel, others are finished in plain concrete or coloured imprinted concrete in environmentally sensitive areas.

The majority of the rail where Supertram runs on streets, is 35G-section grooved tram rail.  For heavy duty crossings, special cast manganese steel is employed for durability and for the remainder of the route BS80A standard rail is used.

Overhead Line Equipment

Power from the network's 12 substations is carried to trams using a double-insulated twin overhead. 107 mm contact wire system.  The wire is supported at a height of between 5 and 6 metres by some 2300 supports.

For maximum environmental and aesthetic benefits, extensive use has been made of lightweight nylon span ropes, rather than the insulated steel wire which is traditionally used on railway networks.  Similarly, use of masts as supports have been kept to a minimum, using building anchorage's wherever possible.  In many cases, working in close consultation with property owners and Sheffield City Council, buildings have been used to provide discrete anchorage points particularly in the City Centre.

Major Structures

Two large viaducts, one underpass and numerous other major structures, including retaining walls, bridges and culverts, have been built. Around 1750 tonnes of structural steelwork, 4,000 tonnes of reinforced steelwork and 23,000 cubic metres of concrete have been used.

There is a six-span viaduct taking the tramway onto the centre of the Park Square roundabout in Sheffield.  Another concrete bridge taking it on to the South and a third bowstring steel arch bridge carrying the alignment into Commercial Street and the City Centre.

The viaduct is of particular interest, being built from 115 pre-cast concrete sections fitted onto 120 tonne units on each of the viaduct's five piers. The bridge follows a double curve and rises and falls throughout its 295 metre length.  Each concrete section is therefore different in size and shape and had to be precisely positioned.

The whole structure is tensioned by stressing wires using a specially designed jack and the joins between sections are welded together using a high performance epoxy mortar glue.

Route Opening Dates