How Madrid built its metro cheaply

Between 1995 and 2007, Madrid's metro nearly tripled in length through a massive expansion program that cost substantially less than comparable projects in other cities—New York's 1.5-mile subway extension and London's Jubilee Line Extension cost similar or significantly higher amounts per mile. Madrid achieved these low costs through a combination of factors: concentrated regional government powers that incentivized fast delivery, streamlined environmental and planning processes, 24/7 construction tunneling, pragmatic trade-offs between design complexity and cost, and investment in experienced in-house engineering capacity, providing a model for other cities seeking cost-effective transit infrastructure.