The 1,070 metre Maastunnel runs under the Nieuwe Maas. Over 75,000 motor vehicles and 7,000 bicycles and mopeds use the tunnel every day. The tunnel also provides eight escalators for the hundreds of pedestrians who go through the tunnel each day. Each escalator is 45 metres long and goes as far as 21 metres below ground level at an incline of 30 degrees. The escalators were assessed as part of an extensive overhaul of the tunnel’s facilities. The experts in Rotterdam found that their wheels had worn down over the years. After looking for a replacement, the city administration found what they were looking for in Rosenfeld.

The transport experts were looking for “the best wheels for the escalators in the Maastunnel national monument.” 3,500 running wheels and chain wheels were needed for the escalators to work properly. A tailored solution was the only answer due to the large wheel diameters involved and the fact that the wheels needed to vary in thickness. The biggest challenge: the wheels had to fit on the existing axle of the step chain. To ensure a long service life, the city’s specifications only permitted a very small amount of play in the wheel. Rosenfeld-based wheel and castor specialists Blickle were contacted as part of the city’s search for a suitable partner.

After analysing the requirements in detail, Blickle’s experts designed a prototype and put it through a demanding series of tests. The wheels needed to be both impact resistant and chemically resistant to water, oil, salt, grease and degreaser. They also needed to have enough friction resistance to avoid slipping on the metal track while withstanding temperatures from minus five to 40 degrees Celsius. The specifications even called for the wheels to be self-extinguishing in the event of a fire and to use thermoplastic materials which meet the user’s fire safety requirements. The outcome of these tests and the cost/benefit analysis ultimately convinced the decision-makers in Rotterdam to award the contract to Blickle in Rosenfeld.