Mobile Rail Milling & Monitoring at Metro Barcelona

Metro systems are subject to increasing train frequencies and decreasing engineering hours for maintenance, mainly caused by the growing population in urban city centers. These circumstances are a huge challenge for rail maintenance which is however essential to guarantee safe and comfortable rail operation at optimal costs.

The main driving forces for rail maintenance in metro systems are operational damages such as rail wear and tear, corrugation and rolling contact fatigue defects (head checks) as well as system-caused defects such as squats. The entire product lifecycle is mainly determined by the initial quality and the chosen maintenance strategy. A high initial quality is the basis for a long service life and can be achieved by considering heat treated premium or super premium rails in critical track segments, such as curves and stations. In addition to the initial quality, operational rail maintenance is at least as important in order to achieve a satisfying rail service life.

One part of the concept is a smart rail monitoring system, where the sensors are applied on standard cars of the customer. With this measuring concept, it is possible to determine the rail condition of the whole network in short time and with manageable effort.

The sensors track

• Rail transversal profile quality
• Rail longitudinal profile quality
• Track gauge
• Additional parameters as e.g. track twist or superelevation

The results form an optimal basis for rail maintenance planning and checking the effectiveness of maintenance actions.

The other part of the concept is the execution of rail milling in track and turnouts. In contrast to conventional rail grinding, the milling process introduces a much lower amount of energy into the rail itself and the rail heats up only to a small extent. Therefore, material transformation in the rail surface is avoided. Due to the procedure, no dust is produced and consequently there is no pollution of the surrounding areas. Furthermore, there are no undirected sparks, which reduces fire hazard to a minimum and is especially relevant in metro tunnels. For rail milling at Metro Barcelona, voestalpine Railway Systems applies the machine MG11.

This maintenance procedure guarantees a particularly careful rail treatment. The combined measuring and maintenance concept is applied at Metro Barcelona with great success. The effectiveness of the milling task is shown by an example of transversal and longitudinal rail profile before and after the measure. As the pictures illustrate, the milling procedure allows for a nearly complete removal of rail defects in transversal and longitudinal direction and to establish a “like new” rail condition after the task.

This regenerative maintenance approach forms the base for maximizing rail service life and therefore to optimize availability and life cycle costs.

The network of Metro Barcelona is operated by Transports Metropolitans de Barcelona (TMB). Due to its long history (nearly 100 years of operation) and the high service quality, Metro Barcelona is a best-practice reference for metros at the Iberian Peninsula as well as in Latin America. Currently, the network contains 8 double track lines, mainly in tunnels. The lines represent the development of metro designs throughout the past century – from the historic Line 1 with Iberian gauge (1,668 mm), to tight tunnels in Line 5 and fully automated trains in Line 9 and Line 10. The energy for the trains is transmitted by a catenary system to ease track maintenance and the exchange of superstructure components. Particular challenges for TMB are different and changing soil conditions, subsoil waters, and the steady requests and guidelines of different district administrations. Additionally, local residents claim operational noise and vibrations in their homes.