AFTER a year in which it set a new world record for underwater concrete pouring and work began on its 800ft central tower, officials say the Forth Road Replacement Crossing is on track to come in on time and on budget.

The bridge is due to open towards the end of 2016, and on current figures is expected to come in at a cost of around £1.4 billion to £1.45bn - down from an original estimate of £1.45bn to £1.6bn.

In June, 35,000 members of the public voted overwhelmingly in favour of naming the bridge the Queensferry Crossing, and between August and September concrete was poured into its south tower foundations non-stop for a record-breaking 15 days.

A total of 16,869sqm of concrete was poured in after being brought across on barges from Rosyth dockyards at a rate of 47sqm an hour, with work completed on September 5.

The concrete plugs for the north and central towers were also completed earlier in the year, paving the way for construction of the towers themselves - including the 820ft central tower.

The project was commissioned amid fears the existing Forth Road Bridge, which opened in 1964, was often carrying twice as much traffic each day than it had been designed to cope with. Although its lifespan was originally predicted at around 120 years, a 2005 study found that its main cables had already suffered 8-10% loss of strength, which would continue to accelerate. A worst-case scenario anticipated traffic restrictions by 2014 to limit the load carried by the bridge, with complete closure following in 2020 - losing a vital link for commuters journeying between Edinburgh and Fife.

Work began on a replacement road bridge across the Firth of Forth in summer 2012. It is the single largest infrastructure project undertaken in Scotland in a generation, with 900 people employed on site and 365 Scottish firms supplying goods or sub-contracted to the project.

Transport Minister Keith Brown said there had been "fantastic progress" over the last 12 months, adding that work remained on track for completion by the end of 2016. Mr Brown said that just over a year ago there were "no foundations" and the "challenging process" of locating steel caissons and cofferdams - watertight structures to help with construction - on the estuary bed was under way.

He said: "Now the caissons and the Beamer Rock cofferdam for the main towers have been drained of water and the towers are beginning to rise up. In doing this, we have seen a world record set for the largest continuous underwater concrete pour.

"On land, the first sections of southern approach viaduct are now ready for launch, marking the first appearance of the actual deck and the start of the bridge itself. Elsewhere, the huge beams for the South Queensferry gyratory bridges have been lifted into place. This progress is achieved through the dedication and hard work of the hundreds of people employed."