Fighting heat in the underground – Rail Technology Magazine (RTM) looks at the successes of the Cooling the Tube programme so far and what TfL hopes to achieve in the coming years.
Despite what was a relatively mild summer, in this year’s June/July edition we decided to take a look at the reasons behind the sweltering temperatures in London’s underground rail network. For the millions of residents and tourists jumping on-board jam-packed Tube trains, temperatures in the Underground are often hotter than those outside, even at season’s peak.
As RTM explained then, the London Clay, through which deep-level tunnels were bored, is largely to blame for this. It originally provided such a cool environment that the network was advertised as a refuge from the warmth. But over time, the thick clay began soaking up the heat generated from the braking trains to the point where its temperature rose from an average of 14° to a whopping 26°.
To prevent this situation from becoming untenable, TfL launched its long-running Cooling the Tube programme, created specifically to address the problem of excessive heat in the Underground.
A number of ‘quick wins’ were achieved at first, such as temporary summer fans across stations; platform-level supply ventilation, where fresh air was pumped via existing shafts; impulse fans to circulate air along platforms; a variable refrigerant flow system to reduce the heat in ticket halls and staff areas; and chiller units at Euston, one of the capital’s most-used stations. Already from these measures, TfL learned that improving temperatures could have a considerable impact on customer satisfaction.