RAIL passengers travelling into London Waterloo next month should expect severe disruption associated with work in what is the biggest investment in this railway for decades.

Network Rail is investing more than £800m in the Waterloo & South West upgrade, designed to provide capacity for 45,000 extra passengers at Waterloo during morning and evening peak hours, equivalent to more than the capacity of the Oval and O2 Arena combined, by December 2018.

The number of passenger journeys on this line has more than doubled in the last 20 years to 234 million and is expected to increase by a further 40 per cent by 2043.

At London Waterloo, the aim is to create a spacious, modern and accessible station concourse by rebuilding the former Waterloo International Terminal; increase services by bringing platforms 20-24 back into use and introducing modern facilities along with new track and signalling; and allow longer 10-carriage trains to run on suburban routes by extending platforms one to four.

Across the network, the Waterloo and South West Upgrade will bring longer platforms for longer trains, at a number of stations on the Reading line; 30 new trains, providing 150 extra carriages between London Waterloo and Windsor; new technology to make trains more efficient and improve punctuality; and improvements to depots and maintenance facilities to look after the network’s biggest ever fleet of trains.

As part of the project, the station has seen the installation of a new footbridge, which connects the main station concourse to the former international terminal.

The new footbridge will be temporarily open to passengers during August, before closing again to enable work on the footbridge and in the international terminal to be completed.

Stewart Firth, director of route sponsorship at Network Rail, said: “The new footbridge is a vital step in opening up the five former international platforms to tens of millions of passengers each year, and it demonstrates the enormous progress that has already been made at the station.

“Passengers will get their first glimpse of the redeveloped international terminal in August while we turn our attention to the other end of the station and extend platforms one to four to accommodate longer, 10-car trains.”

Adam Piddington, customer service director at South West Trains, added: “The completion of the new footbridge is another important step forward in delivering a bigger and better London Waterloo which will allow more and longer trains for the thousands of passengers who use this railway every day.

“The temporary reopening of platforms 20-24 will help to provide some capacity for passengers during the works on platforms one to 10, but we continue to urge passengers to check ahead and plan their journey. The timetable during this time will still be significantly reduced and fewer trains will run.”

From August 5-28, platforms one to 10 at London Waterloo will close while platforms 20-24 will temporarily re-open, with significantly fewer trains running across the network.

During this time, work will start to extend platforms one to four for longer, 10-car trains on suburban routes.

The majority of stations will have fewer services while a small number will be closed, and this will have an impact on passengers and their journeys.

Locally, Alton, Bentley and Farnham stations will remain open although the line is likely to be busier, particularly during the rush-hour period, as passengers who usually travel from alternative stations may temporarily travel from here.

Those travelling from Liphook, Liss and Petersfield stations will see a cut in evening peak-time services.

This will amount to a reduction from two to one train per hour for Liphook and Liss, while Petersfield will see a reduction from four to three trains per hour.

Trains will run with the maximum number of carriages wherever possible and work at Waterloo will continue around the clock in a bid to finish as quickly as possible.

The advice is to travel earlier or later than normal. The busiest trains arrive into London between 8am and 9am and leave London between 5.30pm and 6.30pm. To help those travelling outside of these times, South West Trains will provide longer trains for extended periods.

Alternatively, passengers are being asked to consider not travelling but to consider working from home or planning a summer holiday for all or some of this time.

Those who do have to travel should bear in mind that the majority of stations will have fewer train services; services and stations will be busier than usual, especially at peak times; some journeys will take longer; there will be queuing systems outside some stations; a small number of stations will be closed; and other operators’ services will also be busier while passengers take alternative routes, including London Underground.