The V Shop forms a key part of Bombardier’s current and future train build projects, including the £1bn contract to supply trains for Transport for London’s Crossrail project, which will be called the Elizabeth Line.

The testing and commissioning facility has four train roads for trains to 250m in length. Each train road has full length overhead lines and vehicle servicing and inspection pits and is accessible by rail at both ends, connecting it to the test track and production facilities. The facility can be configured for both initial engineering type-testing on multiple trains and for final acceptance testing and validation.

Carlo Gavazzi’s DuplineSafe fieldbus control technology has been specified to facilitate management of safety equipment such as emergency stop buttons, beacons and access gates to the four lines. Grenville Hunt, electrical engineer at Bombardier Transportation, explains: “We and our contractors Electrical Infrastructure Services already use Dupline at a test track at Litchurch Lane and it’s proved to be so good that when we went out to tender on the V Shop project, we specified its inclusion.”

DuplineSafe is based on the Carlo Gavazzi Dupline fieldbus system. It is approved by TUV Rheinland Group in accordance with the latest safety standards and offers a flexible, easy-to-wire solution complying with IEC/EN 61508-SIL3 EN954 cat 4.

Compared to traditional serial wiring of safety switches, the diagnostics feature is said to be vastly improved due to speed and accuracy. Immediate fault identification helps reduce downtime, especially on large machines. Furthermore, the risk of undetected bridges over safety contacts is said to be significantly reduced.

“Dupline has made a massive difference to us in terms of downtime at the test track, with huge savings in cost and time,” says Hunt. “With so many access gates and stop buttons on the track, every time we had a fault it would take a long time to find out where the problem was. With Dupline’s front-end display, we get a heads-up on exactly which number gate or stop button is faulty.”

Balfour Beatty won the tender to deliver the new V Shop for Bombardier and included DuplineSafe in the electrical infrastructure. “We wanted to standardise safety equipment across the various facilities at Litchurch Lane,” says Hunt. The four lines at the V Shop can act as either test or sales lines, with access and egress measures different depending on whether the overhead line is energised. “Access and egress will depend on whether the line is used for testing or sales. Sales staff are not competent to work on 25kV energised overhead lines, so we need to configure appropriate access. Equally, when used for testing, stop buttons on a line need to shut down adjacent lines. With Dupline, configuration is much easier than other systems we’ve used.”

Dupline is a field and installation bus that offers transmission of multiple digital and analogue signals over several km, via an ordinary 2-wire cable. All modules in an installation connect to the same 2-wire cable which is used to exchange data between modules and between a central controller and modules.

In DuplineSafe, bus-powered input modules provide the interface to safety switches, such as emergency stop palm buttons. The small IP67-rated housing makes it possible to install input modules inside or near the safety switches, even in harsh environments.

By means of the handheld DuplineSafe configuration unit, the user can define the addresses of the input modules to be monitored by the safety relay. In operation mode, the safety relay will trip if one or more of these input modules do not send a valid 'contact closed' signal or if any fault on the bus is detected.

Several relay output modules can be connected to the same bus, and each one can be configured to monitor any input module, making it possible to stop several machines at different locations upon activation of a single emergency stop switch.