From the very beginning, the Bovisa-Saronno line was the backbone of all Ferrovienord traffic: when the network was completed with the incorporation of other lines, all traffic to Milan converged on it.
Doubling the line became a matter of urgency, even though the work would in some cases require radical intervention in terms of urban planning for many of the affected cities. Demolishing buildings, rebuilding stations and diverting roads were just some of the works which would allow the infrastructure to be brought fully into the new century and, above all, towards corporate horizons which were yet to be discovered.
Work began with the first excavation and embankment works in July 1985, and two years later, with the site finally enlarged, the laying of the first gantries began. Finally, at 4.00 am on 5 August 1991, the new Bovisa station began to operate on 6 tracks, and was fully operational by 1993. It would take another 14 years to unravel the final knot in the Cadorna-Bovisa section, the most complex and difficult. 2003 marked the closure of the famous Bullona station and the opening of the new underground station at Domodossola, and the work was completed in 2007.