A previous version of this working paper was originally published in March 2018.

Unique data, in conjunction with a spatial general equilibrium model, isolate commuting benefits from other channels. A novel strategy interacts local innovations with intraurban geography to identify all model parameters (local housing and labor elasticities). Metro Rail connections increase commuting between locations containing (adjacent to) stations by 15% (10%), relative to control routes selected using proposed and historical rail networks. Other margins are not affected. Elasticity estimates suggest relatively inelastic mobility and housing supply. Metro Rail increases welfare $146 million annually by 2000, less than both operational subsidies and the annual cost of capital. More recent data show some additional commuting growth.