Tunnel cooling experiments in place at Holborn station
A DISUSED Piccadilly Line platform at Holborn is being used to test cooling equipment which has been designed by TfL, along with SRC Infrastructure. The cooling panels work by running cold water within a curved metal structure fixed to station tunnel ceilings. An industrial-sized fan circulates air, which has been cooled by the pipework, through gaps in the panel’s structure, providing cooler air for passengers.
The experiments are 70% funded by the Department for Transport and Innovate UK. The disused platform at Holborn last served passengers when the Aldwych shuttle service closed to passengers on September 30,
1994. Since then, it has been used to design and perfect various station infrastructure items.
This is the first stage of testing. If successful, the equipment will be installed at Knightsbridge, with a further stage seeing it installed at four other stations on the Piccadilly Line (Green Park, Holborn, Leicester Square and Piccadilly Circus). If the concept is proven, once long-term capital funding for TfL has been agreed, it will be introduced across the entire deep tube network, consisting of the Bakerloo, Central, Jubilee, Northern, Piccadilly, Victoria and Waterloo & City lines.
The Piccadilly Line was chosen as a new fleet of trains are currently under construction by Siemens Mobility. Once all the trains have been introduced, train frequencies will increase from
24 to 27 trains per hour. As a result, temperatures are expected to increase. Historically the piston motion of trains entering and leaving stations has limited station and tunnel temperatures. However, in time, resignalling could increase frequencies to 33-36 trains per hour within central London. This is when TfL believes that a proven station cooling system will be needed.
Past tests suggested that
120+ year-old deep tunnel stations are inefficient to cool, both from a practical and cost perspective. However, laboratory tests with the new system have successfully reduced air temperatures by between 10 and 15 degrees.