"Transports Metropolitans de Barcelona" is the company operating the metro system in Barcelona. On five lines, it transports more than 300 million passengers every year through the capital of the autonomous region of Catalonia. The network is supplemented by three metro lines. With the new Line 9 Europe longst metro line is currently under construction. At a length of 43 kilometers and with 49 stations, it will link the airport in southern Barcelona with the northern suburb of Santa Coloma de Gramenet.

A total of four Earth Pressure Balance Shields made in Schwanau were delivered to Barcelona for the construction of Line 9. Of these four, the S-461 EPB Shield (diameter of 9,370mm) stands out. On the southernmost section, the advance specialists demonstrated on the site in spring 2009 what exactly is possible in mechanized tunnelling using know-how and top technology. Within 24 hours, they installed 46 rings (each with 6 + 1 segments) and each with a length of 1.5 meters. The result has put everything else into the background: 69 meters of completed tunnelling on Saturday, March 7, 2009. This comes to 360 meters (240 rings) for an entire 7-day week. On April 3, 2009 - after a total of 4,090 tunnel meters - the S-461 reached its target shaft. The S-279 sister machine has been underway on the northern section since 2006, achieving an impressive output of 350 meters a week. The S-279 Earth Pressure Balance Shield reached its target shaft in April 2010 after 9,680 meters. In January 2013 the last of the four EPB Shields completed its tunnelling works.