Tram return loop in Melsele, Belgium
On this site, a tram had to make a curve with a radius of 25m. Tracks systems had to be embedded in the street pavement and constructed on a concrete slab. Noise studies before construction indicated that noise and vibration levels would be very disturbing for the houses very close to the track. The highly damped APT-ST rail fixation system with a resiliency high enough to provide lateral rail deflection and damping was installed to minimise the lateral stick slip of the wheel on the rail that initiates the squeal. The installation was executed following a top down process. Once the track is in place, specially developed rubber caps are placed over the fastener, one on each side of the rail. The caps are designed to protect the fastener from infiltration by concrete that can prevent the working of the spring or even block the movement of the base plate pad.
The performance of this track has been measured after installation and during passage of the Siemens tram (equipped with resilient wheels). Most tram passages did not generate squeal noise at all. For some rare single passages, the measured maximum squeal noise at a vehicle speed of 10-15 km/h at 7.5 m from the track was 80.5 dB(A). In comparison, the calculated squeal noise level for a classical track at 7.5 m from that track was 102.7 dB(A). The very resilient rail system thus reduces the squeal noise, if any, by more than 20 dB(A). This result is very satisfying and leads to more installations of this type to prevent squeal noise in tight tram curves.