South Western Railway delays sparked by a heatwave sweeping the UK could continue into next week, Network Rail confirmed.
Delays and cancellations sparked chaos as huge crowds of passengers were left stranded at London Waterloo.
Network Rail confirmed that the restrictions will be extended over the weekend and possibly into next week.
The emergency speed limit makes journey times up to ten minutes longer.
A Network Rail spokesperson told the Standard: “A number of services on the South Western Rail network will be affected by speed restrictions over this weekend, and possibly into next week, as ongoing hot weather continues to affect track conditions.
“This is to keep passengers safe as in some areas rail temperatures are reaching almost 50c which can cause tracks to expand.
They added that the speed restrictions and service alterations would be kept under constant review.
The news comes after a difficult week for commuters. A chaotic Tuesday evening rush hour saw commuters told to avoid Waterloo altogether.
The sizzling 30C heat caused rail tracks to expand sparking the delays.
Images from Waterloo showed the sheer size of the crowds waiting to board a train at the station.
One person wrote on Twitter: "Chaos at Waterloo. Good luck everyone."
While another added: "This is beyond ridiculous."
While on Tuesday morning there were delays on the Transport for London network as disruption hit the Circle, District, Hammersmith & City and London Overground lines.
A third person wrote: "Absolute bedlam at #Waterloo Station... no one being let in or out. Avoid if you plan on using it immediately."
The heatwave is set to continue for the rest of the week with the Met Office saying temperatures should start to ease off next Thursday.
