First Luxembourg, then Nice, and now Caen has opted for “Affordable Safety”, the solution developed by the VINCI Energies subsidiary, which installs large-scale signalling systems for underground transport. Here’s why.

It may only be half the size of a shoe box but it packs quite a punch: the safety PLC (Programmable Logic Controller) developed by Mobility, the VINCI Energies subsidiary that specialises in road and rail infrastructure integration, prevents the risk of derailment and collision between two trams as effectively as the traditional SNCF system – a cabinet that measures 3 metres by 6 metres.

In this case, smaller really is better. One after another, cities installing tram systems are being won over by Mobility’s small PLC, a solution that is “equally safe, if not safer, than alternative solutions fitted in trains and underground systems,” says Stéphane Berthet, manager of the Tram Signalling business unit at Mobility.

After Luxembourg, whose tram line was commissioned this winter, then Nice, where the installation of PLCs is well under way, Caen is the next city to have opted for “Affordable Safety”, Mobility’s tried and tested solution.

Its compact size means it can be inserted into small cabinets along tram tracks in areas where it would be necessary to build plant rooms to house the two alternative solutions, NS1 relays and computer-based safety systems. Not only does the system save space, it also reduces cost and time. “The safety PLC is 10 to 15% cheaper than the other solutions and cuts installation time by up to one third,” adds Stéphane.

Simple, safe, and non-proprietary

It is easy to add or amend system settings, an aspect that is valued by clients. It’s simply a question of programming rather than wiring. Indeed the software dimension offers increased security, since servicing cabinets can result in connection faults.

“As well as being cost-effective and quick to install, the safety PLC is also attractive to clients as it is a commercial off-the-shelf solution”

Similarly, malicious intrusions into cabinets, where wires might be reversed, can have serious consequences such as collision or derailment. A PLC, however, cannot be tampered with. In this regard, says the Mobility project manager, PLCs offer a higher degree of security than conventional solutions.

As well as being cost-effective and quick to install, the safety PLC is also attractive to clients as it is a commercial off-the-shelf (COTS) solution. Being non-proprietary, the system is not tied to a manufacturer or an integrator. The client retains the right to have it programmed by any market player, which is not the case for proprietary computer-based systems fitted in underground networks for example. This therefore provides additional flexibility.