The Altamont Corridor Express began operations in 1998 with two daily round trips between Stockton and San Jose through the Altamont Pass. Originally known as the Altamont Commuter Express, it was renamed in 2012 to reflect its broader role in regional transportation. The service has expanded over the years, now offering four daily round trips and serving communities along its 86-mile route. ACE provides a crucial transportation link for commuters between California's Central Valley and the Bay Area's tech employment centers.