Measuring exterior train noise and finding suitable test locations
Wout Schwanen: "A train has to comply with a large number of requirements before it is allowed onto the Dutch rail network. There are, for example, restrictions to the amount of noise a train is allowed to produce. Train noise production is determined by a number of factors. Noise emission is influenced by the vehicle itself, the rail roughness and the dynamic qualities of the track. Limits have therefore been set for rail roughness and the track's reverberation time on tracks where sound is measured. There is, in other words, a lot more to a sound measurement than meets the eye. This makes for a varied and extensive job, and one in which we can combine our knowledge of vehicles and track qualities."
Time is money
Time is often limited when carrying out external sound measurements. It is therefore very important that the time available is used as efficiently as possible. Because we measure sound on various channels and at various locations along the track simultaneously, we are able to complete enough measurements in the little time we have to determine your vehicle's noise emission. And if necessary, we also have enough data available to determine how to make the vehicle more silent.
Over the years, we have gained a lot of experience with sound measurements to trains. A good example is the work we carried out for a new type of train to be allowed onto the Randstad light-rail line. Bombardier asked us, as an independent party, to carry out the entire measurement campaign. We chose a measurement location using our ARRoW system. We then measured the rail roughness and dynamic qualities of the track on that location to see if it met the requirements. This location was eventually used to carry out sound measurements to passing, braking and accelerating trains. We used that information to judge whether the train complied with the noise requirements as set by the client.