Thousands of passengers have been warned to expect extended delays to their journeys as Waterloo undergoes a massive redevelopment project.
With 270,000 passengers per day - 130,000 during the peak rush hour of 7am-10am - rail bosses are urging travellers to consider taking holiday, working from home or changing their travel times while the work is being carried out.
Network Rail Chief executive Mark Carne said that he is "worried there will be challenging days" and 'there are going to be days when the service is very hard for people'.
While these developments happen, over 23 days, platforms 20-24 will be open to help accommodate the services that would normally be running from the closed platforms.
If you do end up at Paddington, we're told your ticket will also be valid to get onto the London Underground between Paddington and Waterloo, but you won't be able to get off at any other stations.
Commuters cycle past a bus queue outside Waterloo Station in London.
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Since 1996, there have been over 100 extra services, and 500 extra carriages added to Waterloo station to meet the ever-increasing demand.
The new trains will operate on the Windsor, Reading and west London suburban routes, and will start to come online from mid-2019, with a full rollout expected by December 2020, Bombardier stated.
Becky Lumlock, of Network Rail has said "Now we're in the midst of the largest upgrade of Waterloo for decades and this is a significant part of Network Rail's national railway upgrade plan".
Aerial view north-west of Waterloo International Station.
The impact on commuters' journeys will vary depending on when and where you travel.
There is a cycle superhighway that runs along the route of the Northern tube line in south London.