"Want to experience hell? Try getting on the central line at rush hour in London on a warm day"

London is currently experiencing a heat wave. Temperatures today have hit 33C and with a record breaking 39C temperatures predicted for tomorrow, it is important to stay cool. Unfortunately, travelling in London can be very warm, especially on certain lines. "Want to experience hell? Try getting on the central line at rush hour in London on a warm day."

Certain lines have a reputation of being extremely uncomfortable during the summer months, especially the Central line. There is even a Twitter account dedicated to commuters experiences on the line, @centrallinehell I saw a poll today on Twitter where 80% selected the Central line as the hottest. Is it fair that the Central line is refereed to hell during summer? What is the 'hottest' line in London?

According to figures from Transport for London during last year's heatwave, the hottest line was actually the Bakerloo line with an average hottest temperature of 31.04C. In second place was the Central line with a temperature of 30.47C, third was the Victoria line with 28.03C and with 27.98C, the Northern line came fourth. The other lines without air conditioning experienced 27.3C (Piccadilly line), 26.57C (Jubilee line) and 25.95C (Waterloo and City line). 

The S7 and S8 Stock trains that serve the Circle, District and Hammersmith and City lines, and Metropolitan line respectively, are the only London Underground units to feature air conditioning.  These trains entered service from 2010 to 2017 and only serve the sub-surface lines. The Class 345s that serve TfL rail have air conditioning, some of the trams also feature air conditioning, and the new Class 710s on the Gospel Oak to Barking line have air con. The New Tube for London, which is expected to replace rolling stock on the Bakerloo, Piccadilly, Central and Waterloo & City lines, will experience air cooling. This method is currently used on the Class 378s on the London Overground.

A specially thank you goes to London Overground and Transport for London. Yesterday afternoon a member of staff at Walthamstow Central was handing out a London Overground branded water bottle. In heat waves like this it is important stay hydrated. TfL have produced reminders to "always carry water", and as Geoff Marshall reminds us, we need to carry water "and actually drink it".