In the same week that Britain sweltered in a record-breaking heatwave, Transport for London (TfL) showcased the trial of new technology which could provide much-needed cooler temperatures for passengers using the Deep Tube network.
Tests are taking place with the aim of reducing platform and tunnel temperatures at Holborn station. If the trial proves successful then it could be installed at five stations on the Piccadilly line.
The large LU network has a mixture of deep Tube and sub-surface operations. The latter is operated using air-conditioned trains first introduced at the start of the last decade and there are now 192 S-Stock trains covering 40 per cent of the network.
Meanwhile on the deep Tube system, there are enhanced tunnel ventilation systems on both the Victoria and Jubilee lines. However, on older parts of the LU network there are fewer ventilation shafts and that has led TfL to introduce a range of station cooling systems including industrial-sized fans and chiller units that are able to pump in cold air.
During hot weather TfL monitors track temperatures and undertakes an enhanced regime responding to air-conditioning faults whilst also carrying out regular checks on moving parts of track and crossings. Other measures specific to the railway include having response teams standing by and an enhanced focus on stalled trains and times, crowding and customer advice.
The cooling panel aims to provide cooler air to passenger waiting on platforms as well as mitigating potential temperature increases associated with operating an increased number of trains on the Piccadilly line as part of the line’s future capacity upgrade. The line is also the first of the Deep Tube lines that will receive new-build trains from Siemens, and these are due to begin carrying passengers in 2025.
TfL said that the aim of the new cooling panels is to significantly out-perform the existing Platform Air Handling Units which are currently installed at some stations on the Deep Tube network. Initial results show that the new cooling panels are much better equipped to operate in the unique conditions of the deep Tube environment.
The cooling panel has been manufactured by Direct Engineering/INAL manufactured and OCL installed it at Holborn station. It works by circulating cold water around pipework within a curved metal structure to chill it. It then circulates air, using an industrial-sized fan, through gaps in the panel’s structure, which in turn is cooled. TfL said that the panel could also have the additional benefit of halving operational and maintenance costs, compared to existing technology used to manage temperatures on Tube lines.
Previously it has been challenging to lower temperatures on the Deep Tube lines because traditional cooling systems have proven prohibitively expensive and difficult to install within the 120-year-old tunnels and stations. However recent tests on a prototype cooling panel in a laboratory environment found temperatures were reduced by 10-15 degrees in the vicinity of the panel. TfL is now keen to see if this can be replicated on the disused platform at Holborn, which mimics the live environment that these panels would operate in.
The trial is part of the Government’s TIES Living Lab programme, which is a collaboration of 25 partners focusing on 10 infrastructure, data research and digital demonstrator projects, of which the cooling panels are one, and which is funded in the main by the Department for Transport (DfT) and Innovate UK. For this project, TfL said that the DfT and Innovate UK provided some 70 per cent of the costs.
However, TfL said that any installation is remains the subject of funding and effectiveness of the equipment.
Although initially TfL is investigating the possibility of installing the cooling panels on the Piccadilly line, there could be further opportunities to install them on the Bakerloo, Central, Jubilee, Northern, Victoria and Waterloo & City lines as well.
Further testing will need to take place in a station open to passengers (Knightsbridge) before it could look to potentially introduce them at a further four stations on the Piccadilly line – Green Park, Holborn, Leicester Square and Piccadilly Circus. Modelling by TfL suggests that these stations (and Knightsbridge) would require cooling to mitigate temperate increases associated with the increased frequency from 33 trains per hour to 36.
TfL could then identify other locations where the panels could make a difference for passengers. However, TfL admitted that continuing the trial would ultimately be subject to there being sufficient long-term capital funding available.