Service is managed by the San Joaquin Regional Rail Commission, and operations are contracted to Herzog Transit Services, using AAR assigned reporting mark HTSX. The 86-mile (138 km) route includes ten stops, with travel time about 2 hours and 10 minutes end-to-end. The tracks are owned by Union Pacific Railroad. ACE uses Bombardier BiLevel Coaches and MPI F40PH-3C locomotives.
Service began on October 19, 1998, with two weekday round trips. A third round trip was added in May 2001, followed by a fourth round trip in October 2012. As of 2016, average weekday ridership is 4,900.[1] Under the ACEforward program, a number of improvements to the service are being considered. These include a rerouted line through Tracy, an extension to Modesto and Merced, and connections to BART at Union City and Tri-Valley.