Milan Metro Line M4 cost escalates; to be completed in phases by July 2023, Italy June 12, 2018 | Europe Finance The project cost of Milan Metro Line 4 (M4) has escalated by EUR313 million, taking the total cost for the line to over EUR2 billion. The additional cost is to cover delays in work, improve constructi... This content is available to only subscribers. Username or E-mail Password Remember Me Forgot Password