RandstadRail Independent Safety Assessment (ISA)

RandstadRail Independent Safety Assessment (ISA)
03 August 2015

RandstadRail is a light rail transport system  in the west of the Netherlands, connecting the city centres of Rotterdam and The Hague via Zoetermeer and entered into full service in 2011. 

The ‘backbone’ of the network is a regional rail route that already existed between the cities, but was to be upgraded to support ‘metro’ style frequencies and more stations, before connecting directly to the transport systems within each city at either end. As a result, RandstadRail is a hybrid of regional and urban systems, featuring low-floor tram-train style carriages and high-floor metro vehicles. 

The creation of a new fully-integrated transportation network required a number of adaptations to the existing infrastructure, including the construction of new overpass junctions, changes to the power supply, installation of the ATP safety system  and new passenger signage and information systems. New low and high-floor vehicles would also need to be admitted into service.

Independent Safety Assessment

We were appointed as the Independent Safety Assessor (ISA) at the project's highest level to ensure that the system satisfied the Light Rail Safety Standards Document and that the risks associated with the introduction of the Tram-Train system were acceptable and monitored.

System safety is one of the major risk factors for approval and, as a result, all major suppliers of subsystems were obliged to submit a ‘safety case’ with an ISA statement. 

The project was based on the application of the EN 50126 norms and procedures and the Quantified Safety Goals published by the Dutch government. Our assessment was conducted based on the safety plans drawn-up by the project within this framework.

EN50126 is particularly relevant in a project like RandstadRail, where an entirely new integrated system is to be created from legacy sub-systems.

In this context, a structured approach, with careful consideration of the integration aspects and coordination between suppliers and contractors, is vital in order to achieve a safe, working system from the constituent parts.

After detailed evaluation of the documentation, in particular the interactions between the various sub-systems, our independent assessment declared the risks acceptable.

This conclusion was based not only on the system risks identified, but also the activities that were to be carried out by the regional transport authorities in their roles as both Infrastructure Manager and Operator.

With the RandstadRail system declared compliant with Dutch safety regulations by the ISA and by safety authority, the system could proceed into full service.