LONDON Underground's 2·4 km Waterloo & City Line is closed to traffic between April 1 and September 1 as Metronet undertakes a £40m upgrade under its 30-year Public-Private Partnership contract.

As well as relaying track to restore the line speed to 55 km/h on straight sections and improve the minimum round trip time from 11·12min to 9·81min, Balfour Beatty Rail will be modifying signalling and installing a Bombardier EBIscreen control system that should permit five trains to operate on the route at the same time instead of four.

Maintenance-intensive bullhead rail on longitudinal timber sleepers is to be replaced by 9076m of flat-bottomed 113A Grade A rail on concrete sleepers, while 1432m of check rail is to be installed on the tightly-curved route between Waterloo and Bank. The positive conductor rail is to be replaced with Type No 6 from Brecknell Willis, made of aluminium with a steel cap, and the provision of a drainage channel should reduce signal failures caused by water ingress.

The fleet of 20 cars built to LU's 1992 stock design will be refurbished by Wabtec at Doncaster, and fitted with CCTV.

Train and depot work as well as station enhancements including the installation of platform ramps to improve accessibility are supplemental to the track and signalling upgrades specified by the PPP contract.

Completing the programme on schedule will require work to be undertaken 24h a day in three shifts seven days a week, with 240 staff on site in a 24h period. LU will save £3m by agreeing to the five-month blockade rather than 87 weekend closures and others of up to 30 days to complete the work by March 2007. According to Metronet's Programme Manager Jack Carter, this would have been 'horribly inefficient'.