Utrecht tram integration testing


In autumn 2020, Ricardo’s rolling stock testing team helped the city of Utrecht upgrade a key tram route that serves the city’s busy mainline station.

The Nieuwegein/IJsselstein Fast Tram ('SUNIJ-lijn') route first opened in 1983 with a fleet of single-articulated, high-floor trams.

As the original vehicles approached life-expiry, the city opted to replace them with a lighter, low-floor vehicle as part of a wider refurbishment of the route’s infrastructure.

In 2019, BAM Infra Rail was contracted to oversee the main infrastructure works, including track replacement and the renovation of the tram stops to accommodate the new low-floor vehicles to be supplied by Spanish manufacturer, CAF.

Having successfully worked on the testing programme for the Uithoflijn, a nine-stop tram line in the city that opened in 2019, Ricardo was again appointed to assist BAM in meeting its contractual duties with regard to system integration testing, with a focus on the vehicle-track interface.



Ricardo and BAM’s technical teams began preparations more than a year in advance, working together to define the final programme of tests that would be required to satisfy BAM’s safety and contractual requirements.

The resulting plan included over 100 separate tests, factoring in differing locations, speeds and vehicle configurations.

In the period leading up to the physical testing, Ricardo’s test leader kept in close contact with the various technical disciplines to ensure all starting conditions would be met and that stakeholders were aware of the schedule and had the most relevant safety instructions.

Once the main infrastructure works were completed in summer 2020, the overnight testing phase could commence on the new tracks, to be conducted under strictly controlled protocols.

The programme opened with a route clearance verification test where the vehicle was guided at almost walking pace through the full cycle of the route, with polystyrene foam affixed to critical locations on the tram.

Once it was confirmed that the vehicles kept a safe distance from safety barriers, platforms and other trackside apparatus throughout the entire route, the speed was gradually increased for subsequent test runs to assess driver sightlines or the vehicle’s interaction with track points, crossings and lineside signalling.

During these early test runs, a Ricardo Safety Leader was present at all times to act as a second ‘pair of eyes’ for the tram driver and to maintain contact with both the traffic controllers and the onboard Test Leader.



Despite the necessary social distancing measures required due to COVID-19, the entire test programme was successfully completed so that the application to enter the new infrastructure into service could proceed.

The introduction of the low-floor CAF vehicles in December 2020 means the SUNIJ fleet is compatible with those that serve the Uithoflijn, which also operates from Utrecht Central Station and extends out to the Science Parc.

This means that as well as providing passengers on the SUNIJ-lijn with more comfortable and accessible vehicles, the operator of Utrecht’s tram can expect to gain long-term operations and maintenance efficiencies now that both lines use the same vehicle model.


BAM Infra Rail

Key Services

Rolling stock integration testing

Start and end dates

09/2020 - 12/2020


The Netherlands, Utrecht

Railway testing and measurement
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