Public transport overheating?

In an article posted on the company's website, South West Trains explained why the heat was affecting their services.

South West Trains says that the speed restrictions have now been lifted, but that the delays will continue for a couple of hours.

The concourse at Waterloo was packed with frustrated commuters this evening, as services were affected by the hot weather.

South West Trains put speed restrictions in place between Clapham Junction and Waterloo - because the tracks were struggling to cope with surface temperatures approaching 50 degrees Celsius.

Trains were limited to 20 miles an hour, with many services delayed, cancelled or altered.

We've recorded the temperature onboard a 38 bus between Grays Inn Road/Holborn and Essex Road, Islington this afternoon. Our Political Correspondent Simon Harris's tweets accompany each image.

On Friday, the Mayor Boris Johnson promised to fix the problem, and Transport for London claimed an 'army of engineers' would work throughout the weekend to get the air conditioning working.

But many commuters have complained that the top deck of the new bus for London is still "unbearable"

Our correspondent Simon Harris has been onto a Route 24 'Boris Bus' and recorded sweltering temperatures:

Windows on the New Bus for London don't open because it prevents the air cooling system from working, says Transport for London - a disaster for passengers when the air cooling system doesn't work in summer temperatures.

TfL says ‘air-conditioning’ is ruled out on buses because the unit would make buses heavier and mean they consume extra fuel making them less environmentally friendly.

Some London buses – including the New Bus - have air cooling, where air is streamed through the upper deck.

TfL says that where vehicles are fitted with air cooling, opening windows detract from the cooling by dissipating the flow of air; so on New Bus for London vehicles the windows don't open.

Mike Weston, Operations Director for London Buses, said:

“We are aware of some technical issues with the ventilation and air cooling system on some of the New Bus for London vehicles on Route 24. Our suppliers are working to fix the issue as soon as possible.

When the air chill system is fully operational we are finding temperature levels are comparable to other buses in our fleet fitted with a similar system.

As you would expect with the introduction of a large fleet of new buses, there will be teething problems and we are working hard to minimise the impact of these on our passengers.”

Mayor Boris Johnson told us that he'd thought the problem was fixed...