SCADA system for Medway Tunnel

Vital Technology has provided a multi-discipline SCADA system at the Medway Tunnel under the River Medway between Strood and Chatham in Kent on the south coast of England.

The work at Medway has been a supervisory control and data acquisition (SCADA) system replacement project in which Ematics, a subsidiary company within Vital Technology specialising in SCADA, have installed a SCADA and programmable logic controller (PLC)-based control and monitoring system to facilitate tunnel operation. The custom-developed SCADA system at Medway is a Graphical User Interface (GUI) which interacts with diverse subsystems including video surveillance, access control, fire systems, intruder alarms, radio rebroadcast and a video incident detection system.

The system provided by Vital consists of a SCADA ‘client-server' layer which provides the operator with the GUI required for tunnel operations and a PLC control layer which handles the business logic and tunnel control activities. In the event of SCADA or PLC failure, there is automatic transfer to a back-up system such that no single point of failure can interrupt tunnel operations.

The Medway Tunnel works includes the supply and installation of 24 video surveillance cameras for which two independent video wall systems were provided in separate locations. These video streams are processed and distributed to the video walls through DigiWall software. This software is also client-server based and has been developed in-house by Sicura Systems, another Vital Technology company. Sicura also specified and supplied analogue and IP-addressable CCTV cameras from Bosch which are used for both standard surveillance and the automatic incident detection system.

The video incident detection system comprises 32 dedicated fixed-focus cameras installed by Vital Technology at strategic locations throughout the tunnel. It was specified, evaluated and procured by Vital as part of the contract. The existing life-expired radio rebroadcast system in the tunnel was also replaced. Vital Technology used its consulting expertise to supply an appropriate industry offering and supervised the installation.

The radio rebroadcast system consists of tunnel antenna distribution infrastructure including radiating cables while the main equipment features combiners and base stations. There are 25 hand-held maintenance radios and an antenna system for above ground which includes related hardware. FM radio break-in was also provided, allowing the tunnel operators to broadcast messages directly to drivers' car radio, so allowing safety-critical announcements to be made in the event of an incident.

Harold Trunley, Managing Director of Vital Technology, said: "Typically, up to six separate companies would be involved on such a project but Vital used its wide-ranging project management expertise to ensure all subsystems were built to exact specification and delivered on time. "We were able to report directly to our client Medway Council while working closely with the council's project manager, Serco."

Phil Moore, Head of Highways and Parking Services at Medway Council, said: "Working with Vital Technology developed into what has become a good partnership. A project of this size has not been without its problems as anyone in the industry would appreciate, but working in partnership with service-specific professionals from a number of supply chain organisations has resulted in a system that provides a high level of safety for the travelling public." He added: "We would encourage road tunnel operators to visit Medway and see the completed project for themselves."