The UK’s Network Rail (NR) has announced that contractors working on the £2.3bn investment programme to upgrade the existing railway for the Crossrail programme have now passed the halfway milestone.
Overseeing the Crossrail programme, NR said the project is running on time and on budget.
Three-quarters of the Crossrail route runs above ground on the existing rail network through outer London, Berkshire and Essex.
As part of the work, contractors are adding capacity on key parts of the network, including more than 30 miles of new track, construction of a new flyover in Hillingdon and a new dive-under tunnel at Acton.
UK Rail Minister Claire Perry said: "These works are a vital part of delivering Crossrail, and the halfway point is a real milestone in Europe’s largest infrastructure project.
"The vast improvements on the existing rail network go hand-in-hand with the impressive tunnelled sections.
"Together, they will create a transformational rail link that will bring better and faster journeys for passengers across London and beyond from 2018, boosting jobs and economic growth."
The investment also includes improving 29 stations and electrifying the Great Western Main Line (GWML) in west London and Berkshire to allow for the introduction of new, quiet, greener and more reliable electric trains.
Work also includes delivery of more than 40 lifts, platform extensions at 16 locations to accommodate longer trains and a complete rebuild of nine stations to provide new, spacious, bright ticket halls.
Network Rail CEO Mark Carne said: "As part of our railway upgrade plan, we are delivering this vital component of the Crossrail programme on time and on budget.
"There is still a huge amount of work to do but we are on schedule to provide passengers in London and the South East with better connections, quicker, easier journeys and vastly improved stations."
So far, the first section of the Stockley Flyover, a huge new rail bridge at the junction to Heathrow, has been completed.
Upgrades are being carried out at stations to the west of London, including major overhauls at Ealing Broadway, Hayes & Harlington and West Ealing.
Work to electrify the GWML, including the demolition and replacement of six bridges over the railway in Slough and South Bucks was also part of the work.
A modern signalling system has been installed between Heathrow Junction and Reading, which will improve reliability and support the future operation of Crossrail and Great Western services.
In East London and Essex, an interim station has been opened and the old station demolished at Abbey Wood.
Construction of a new station has been initiated and more than a mile of new track has been installed.
Following completion, the £14.8bn Crossrail route will serve 40 stations and run more than 100km from Reading and Heathrow in the west, through new twin-bore 21km tunnels below central London to Shenfield and Abbey Wood in the east.
Image: New tracks in Abbey Wood. Photo: courtesy of Crossrail/Network Rail.