Underpass means all works which allow the crossing of roads and/or railways at staggered levels. This that we present is the underpass of via Montecassino to Seveso that we have realized for FerrovieNord within the project of requalification Saronno-Seregno: a long and complex work carried out between 2014 and 2015 that today offers the opportunity of a fast and safe transport to the citizens. Mobility also involves construction.