The signal safety monitoring system for Gothenburg Tramways has now entered its 25th year of uninterrupted operations. Traffic managers at TLI, Gothenburg Tramways’ traffic management and information unit, use the system round-the-clock to remotely monitor switches and signals and keep tram traffic running smoothly and safely. Over the years, the proprietary Infracontrol system solution has undergone a number of upgrades but remains largely unchanged. Now, in a further modernization, the server hardware is being replaced by virtual servers, for continued secure operations.
Mimmi Mickelsen, track safety planning officer at the City of Gothenburg Traffic and Public Transport Authority, is responsible for keeping the system running and doing its job:
“Having worked without problems all these years, the system has been a boon for our traffic managers, says Mimmi Mickelsen. Now we’re updating the system again by switching to virtual servers to ensure operation of this important support system for many years to come.”
Long and faithful service
There are a number of signal boxes in the Gothenburg Tramway network. They use signals to control tramway switches and are subject to high safety standards. Infracontrol developed a control and monitoring system for this type of essential installation as an assignment from the Gothenburg Traffic and Public Transport Authority back in 1996. The system has been in use round-the-clock ever since by TLI – Gothenburg’s Traffic Management and Information unit – to remotely control and monitor signals, switches, switch heating and other peripheral functions. The system has now entered its 25th year of faithful service, and it’s time to safeguard continued operations. Project manager Johanna Einarsson at Infracontrol, who has been involved right from the start, tells us:
“Over the years, we’ve delivered 12 such systems to signal boxes in the city. The systems have undergone a number of upgrades, and now we’re carrying out of further modifications to virtualize the servers located in each of the installations. The computer hardware is replaced by an equivalent server function in the central environment at the Transport Authority, providing operational and admin benefits.”
User-friendly images and an intelligent logging feature
Two of the most important functions are early detection of the risks of disruptions and providing traffic controllers with reliable decision support data. Important information is therefore shown in clear, easy-to-use overviews to make sure all of it reaches traffic controllers, enabling them to take the necessary measures. The system has also an intelligent function that logs all signal changes in the signal boxes at very high time resolutions:
“The logging function provides a full overview of the sequence of all events in the signal boxes, explains Johanna Einarsson. Logged information is shown diagrammatically or through a playback function that is an excellent tool for analyzing traffic holdups.”
Johanna tells us that the user-friendly features, combined with the flexible SCADA and PLC-based solutions are the key to the system’s excellent longevity.