ENGINEERS gearing up to ease a giant west Reading railway bridge into place at Christmas fear the weather could prove their biggest challenge.

Network Rail contractors are already preparing snow blades and ploughs if a cold snap threatens the next crucial stage of the �850m Reading Station upgrade - installing a 1,680-tonne reinforced concrete replacement bridge at the Portman Road end of Cow Lane.

Project manager Matt Jackson's team will shut Cow Lane for five weeks from Monday, December 19, in partnership with construction company Bam Nuttall.

He said: "This is one of the largest projects in the UK at the moment and a key milestone in the Reading upgrade. We have been preparing for months and you can plan for most things but if there's heavy snow or flooding we could be really up against it. We can work in snow but we need the weather to stay good so we can complete the job."

The main operation begins at 5pm on Christmas Eve when engineers shut the major rail freight line and spend 12 hours dismantling the old bridge and stripping out the tracks for re-use. A convoy of lorries will ship the 7,500 tonnes of bricks and rubble for re-use at a new train maintenance depot being built on land in Lovelock Road.

On Boxing Day a huge 66-axle Self Propelled Modular Transporter (SPMT) will carry the pre-prepared bridge from a depot in Cow Lane where assembly began in May. The remote controlled vehicle inches forward at considerably less than walking pace - taking 12 hours to complete the 80m (262ft) journey - and engineers are already preparing a compacted walkway to make it as smooth as possible.

The most crucial stage involves turning a bend near the First Great Western depot where there is only a 50cm (20ins) gap between overhead wires controlling railway signalling for the entire region.

Spectators will be able to watch the action from a viewing platform in the Dairy Crest yard in Portman Road.

The new bridge, wide enough for taller vehicles and buses to pass through, will be shored up with concrete and polystyrene blocks before the old tracks are re-laid and a new two-carriageway road and pavements are built.

Workers will also use the five-week closure to prepare concrete support columns for the bridge to replace the one at the Cardiff Road end of Cow Lane, which will be built in situ and completed next year. High-sided vehicles will only see the benefits after summer 2015 when the road beneath the bridge is lowered by 1.5m (5ft).

Mr Jackson admitted it is "sad" demolishing a Victorian bridge built during the Brunel era, but said: "More freight than ever is using the railways and we have got to move with the times."

The new Reading Station, with five extra platforms and two new entrances, will be completed in 2015.

l Cow Lane will be shut between Safestore and Salisbury Road from 6am on Monday, December 19, to Monday, January 23, and between Safestore and Cardiff Road from 8pm on Monday, January 23 until 6am on Monday, January 30.

Diversions are via Oxford Road and Caversham Road but access to Safestore, Cardiff Road and Salisbury Road will be maintained throughout.

The plans will be on display from 8am-7pm on Tuesday, December 6. at Reading Station.

Contact 08457 114141 or see www.networkrail.co.uk