UK Network Rail has completed a £4.5m section of the £800m Waterloo & South West Upgrade.
Equipment has been replaced and signalling at Queenstown Road improved as part of the upgrade, which is expected to increase capacity at Waterloo by 30% by December next year.
Network Rail route managing director Becky Lumlock said: “Christmas provides us with a great chance to deliver vital aspects of our Railway Upgrade Plan while causing the least amount of disruption to passengers.
“Our work will now continue behind the scenes in the international terminal, but I’d like to thank all those who gave up their Christmases in order to deliver these upgrades.”
Other modifications included complex signalling and power modifications at Waterloo to enable work throughout this year and continuing hydro-demolition work in the former International Terminal at Waterloo in an effort to re-open the five former international platforms.
Network Rail engineers also created openings on platforms one and two, as well as at three and four.
The 15m-long holes will become extra staircases that will provide additional access to London Underground services after the extension of platforms by improving passenger flow through the station.
Network Rail invested £103m for works over the recent Christmas period across the UK to perform around 200 upgrade projects.
The Waterloo & South West Upgrade is set to continue this year.
Network Rail plans to rebuild the former International Terminal, and extend platforms one to four to accommodate longer trains.
Meanwhile, South West Trains is set to introduce a fleet of 30 brand new trains to provide 150 extra carriages from April.
Image: Network Rail engineers installed a temporary cover over holes in platforms one and two, and platforms three and four to keep passengers safe before the entrances are fully opened. Photo: © Network Rail.