Approximately £30m worth of works have been successfully completed as part of preparing the existing railway for the Crossrail programme across London, Berkshire and Essex.
The works, which were carried out by more than 3,000 workers on the railway over the four-day Easter weekend, will integrate the new Crossrail tunnels beneath London with the existing rail network.
Network Rail Crossrail programme director Matthew Steele said: "Our orange army worked tirelessly over the Easter weekend to deliver a staggering amount of complex work.
"As three quarters of the route will run above ground on the existing rail network, the improvements we have delivered are crucial to the successful completion of the new railway."
Under the £30m package, work was carried out to electrify the railway in west London and Berkshire, paving the way for the introduction of new, quicker, quieter and more reliable electric trains from next year.
The scope of work also included the extension of platforms at various locations, including West Ealing, Southall and Hayes & Harlington stations in order to accommodate longer trains.
In order to increase capacity and improve reliability of the railway, major trackwork was carried out at locations, including Maidenhead, Old Oak Common, Stockley and Shenfield.
According to Network Rail, the work is important as three quarters of the Crossrail route will run above ground through outer London, Berkshire and Essex, bringing 1.5 million more people within 45 minutes of central London.
In February, London mayor Boris Johnson named the £14.8bn Crossrail railway the Elizabeth Line in honour of the Queen.
The Elizabeth Line will deliver a direct link between all of London’s main employment centres, connecting Heathrow with Paddington, the West End, the City and Canary Wharf.
Trains will start operating in five phases.
These will be Liverpool Street to Shenfield next May; Heathrow to Paddington in May 2018; Paddington to Abbey Wood through new central tunnels in December 2018; Paddington to Shenfield in May 2019; and full through service including services to Reading in December 2019.
Construction also started on a new station at Abbey Wood with several huge pre-cast concrete slabs lifted into place to form the base of the new two-storey building.
Crossrail surface director Matthew White said: "The Crossrail project will provide a step change in public transport for many thousands of people in outer London, Berkshire and Essex.
"The programme of work delivered by Network Rail over Easter brings us a step closer to delivering quicker journeys, improved stations and better connections for local people along the route."
Image: Trackwork at Shenfield. Photo: courtesy of Crossrail Ltd.