A recent expansion of the San Francisco Bay Area's heavy rail system represents an exogenous change in the accessibility of inner-city minority communities to a concentrated suburban employment center. We evaluate this natural experiment by conducting a two-wave longitudinal survey of firms, with the first wave of interviews conducted immediately before the opening of service, and the second wave approximately a year later. Within-firm changes in the propensity to hire minority workers for firms near the station were compared with those located farther away. Also estimated was the effect of employer distance to the new stations on changes in propensity to hire minorities. Results indicate a sizable increase in the hiring of Latinos near the new stations, but little evidence of an effect on black hiring rates. (Contains 5 figures, 7 tables and 29 footnotes.)