An £81m scheme by Network Rail to renew infrastructure in the Hither Green area of South London has reached halfway and is on track to hand back a much-improved railway for passengers, while also marking the end of London Bridge Area Signalling Centre as an operational location.

The project means the whole main line from Charing Cross and St Pancras International to Chislehurst is under the control of Three Bridges Rail Operating Centre near Gatwick in Sussex, signalled from modern WestCAD workstations.

Network Rail and its contractors have been on site at Hither Green since Saturday morning replacing the 1976-built signalling equipment, which was reaching the end of its life and increasingly difficult to maintain or operate reliably. Teams are installing 92 LED signal heads, and replacing almost 90 track circuits with 262 Frauscher axle counters, along with enhancing 86 sets of points and laying 24km of power cable and 19km of fibre telecoms cable.

In addition, the local power supply is being upgraded and made more resilient and turnback facilities are being put in place at Hither Green, Grove Park and Lee.

Blockade Director Jon Ruch said: “This is a massive project and much-needed as we know passengers in South London have been suffering increasing disruption in this area. The move to axle counters will improve reliability as we won’t have to maintain insulated block joints and impedance bonds, and we’re also building in greater operational flexibility with new turn-backs at Lee, Hither Green and Grove Park. People often forget the impact of cable faults on reliability too, and relaying all the power supply and telecoms will have a massive positive impact.

“On top of all that, for many of us who worked on the Thameslink Programme, this is really the final part of the jigsaw we started many years ago and puts control of the busiest and most difficult to manage part of our network in a single location with modern technology.”

In addition to the new signalling equipment, a great deal of work is being undertaken at stations, from new drainage and platform edging at Chislehurst, to ongoing work at Hither Green station itself, which is getting new platforms and canopies.

London Bridge ASC was built in 1974 with an NX panel and first started signalling trains in 1975, absorbing a variety of smaller boxes, from the two-man level-frame Borough Market Junction, to the 1962-era panel at Hither Green. At its largest it was one of the busiest boxes on the whole railway, controlling trains from Charing Cross on the routes out to Kent through Greenwich, Lewisham, Grove Park, and the four tracks down to Norwood Junction.

Some of its equipment is being retained for use as spares elsewhere on the network and the building itself is being assessed to see what use it can be put to.

Three Bridges control centre now fringes with Ashford IECC and Victoria ASC at Chislehurst.

The railway is closed to trains on the main line through Hither Green, along with the Bromley North and Sidcup branches. Services resume on Monday, 3 August.