Extracting heat from the London Underground Network is a huge and ongoing engineering challenge, especially on the deep tunnel lines. To meet this need Transport for London (TfL) established a dedicated programme team to provide a variety of solutions including mid-tunnel ventilation and cooling, station cooling and regenerative braking on vehicles.

Keeping the Tube’s customers cool involves utilising current technologies as well as making best use of more traditional approaches.

Firstco were approached by Mansell Construction Services to design a control system that would control the cooling fans and dampers to be installed at four mid–tunnel ventilation shafts (MTVSs) on the Victoria line, thus doubling the air flow through these tunnel sections.

The control system consists of a network of programmable logic controllers (PLCs) that interface to a central cooling system (CCS), providing operators with real-time monitoring and performance trending. The control system architecture required the design of an industrially robust network to cope with the harsh underground environment.

In 2009, Westermo Data Communications were approached to supply much of the industrially hardened networking equipment used to connect the central cooling system to the PLC equipment used to provide the control and monitoring functionality within the four MTVSs.

In order to obtain the reliability and performance required from the network, it was decided at an early stage to adopt ADSL as the communications technology as PSTN circuits already existed and could be easily migrated over to an ADSL service. By using the Westermo DR-250 ADSL router, IP traffic could be transferred at rates of up to 8MB, broadband speed. This high bandwidth, ‘always on’ connection enables engineers and operators to make informed decisions based on alarms indicating fault conditions generating from the shaft and station plant.

Additionally a data historian was utilised to provide real-time data logging and archiving functionality generating performance reports for the client.