The public transport in Madrid, Spain, and in particular the subway infrastructure is a key element in the mobility of the Madrid community. However, this type of transport can be a source of vibrations and is therefore seen as a potential threat to the surrounding metro tunnel infrastructure, and even to historical and other buildings at the ground surface. Important parameters are the trains, the infrastructure and superstructure of the rails and the relative position of tunnels.In recent years, the sensibility of the public opinion to noise contaminations has increased drastically, forcing the metro company’s technicians to use advanced corrective actions. To be able to study these effects, metro companies use advanced testing equipment, such as the portable multi-channel analyser LMS Pimento, to investigate the noise and vibrations generated by rolling metro vehicles.
Spain’s cosmopolitan capital offers a widely distributed metro network of over 227 kilometres and transports over 544 million passengers a year. The metro company’s 5,320 employees organize the daily exploitation of 12 metro lines, 237 metro stations and 1,602 metro carriages. The Management and Maintenance Techniques Department of the Fixed Installations Unit of Metro de Madrid is responsible for the analysis of noise and vibrations generated by the metro trains and to define and implement the corrective actions.
“The analysis and reduction of the noise and vibration levels transmitted to our network’s infrastructure and surrounding superstructure are of key interest to our company. The solution we find most efficient is an anti-vibration system, as it heavily reduces the structural propagation of noise and vibrations,” stated the technical department responsible of the Fixed Installations Unit.
The performed studies analyze dominant frequencies of railway tracks, vibration levels in the tunnels and on streets, and structural as well as secondary noise levels. These investigations also examine the effectiveness of different anti-vibration solutions and measure rail displacements to avoid instabilities of the passing train. The engineers also study the durability of these systems by regularly executing measurement campaigns.
Furthermore, the engineers execute these measurements in a systematic way, with the exact type of train that is used commercially every day. The administrative and technical maintenance unit of the Fixed Installations Unit concluded, “The reported analysis results and data comparisons enable us to efficiently guard the performance of our installed anti-vibration systems and evaluate new solutions for reducing noise and vibrations.”
“After evaluating various extensive market studies, we identified LMS Pimento as the most powerful system with a yet versatile offering of analysis functions,” explained the technical responsible. “We use this highly reliable testing system not only for measuring noise and vibrations, but also for other assignments, as it is a portable analyser that connects with any type of sensor. Its user-friendly utilization and easy-programmable operator interface were other decisive factors. We are thinking of using more LMS Pimento systems and are planning to further extend the scope of measurements we perform with LMS Pimento.”
Madrid is not the only European city where LMS Pimento is used in metro facilities. Met.Ro. in Rome and RATP in Paris are other metro companies that leverage LMS Pimento measurement systems to reduce noise and vibrations that are generated by rolling metro vehicles.
