Altamont Corridor Express

Altamont Corridor Express
Altamont Corridor Express
	Altamont Corridor Express train climbing its namesake Altamont Pass
Overview
Owner	San Joaquin Regional Rail Commission
Area served	San Joaquin Valley, Tri-Valley and Silicon Valley
Transit type	Commuter rail
Number of stations	10
Daily ridership	2,500 (weekdays, Q4 2023)
Annual ridership	576,300 (2023)
Headquarters	Robert J. Cabral Station; Stockton, California
Website	acerail.com
Operation
Began operation	October 19, 1998
Operator(s)	Herzog Transit Services
Reporting marks	ACEX
Infrastructure manager(s)	Union Pacific (Stockton–Santa Clara); Caltrain (Santa Clara–San Jose)
Number of vehicles	10 locomotives, 30 passenger cars
Train length	1–2 locomotives, 4–8 passenger cars
Technical
System length	85 mi (137 km)
Track gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Average speed	39 mph (63 km/h)
Top speed	79 mph (127 km/h)
System map
	Legend
Valley Rail (2026)
	Amtrak Coast Starlight
	to Seattle
	Bus connection to
	Sacramento Airport
	RT to Watt/I-80
	Amtrak to Auburn & Chicago
	Sacramento County
	San Joaquin County
	Amtrak San Joaquins
	to Sacramento
	Amtrak San Joaquins
	Oakland │ Bakersfield
	Altamont Corridor
	Vision (2026/2030)
	Altamont Corridor
	Vision
	San Joaquin Co.
	Stanislaus Co.
	Phase 1 (2026)
	Phase 2 (2030)
	Stanislaus County
	Merced County
	Layover and
	maintenance facility
	San Joaquin County
	Alameda County
	Altamont Pass through
	the Diablo Range
	Coyote
	Creek
	Alameda County
	Santa Clara County
	Santa Clara–
	Great America
	Caltrain to Tamien
	Coast Starlight to Los Angeles
	All stations are accessible
	This diagram: view; talk; edit;

The Altamont Corridor Express (also known as ACE, formerly Altamont Commuter Express) is a commuter rail service in California, connecting Stockton and San Jose during peak hours only. ACE is named for the Altamont Pass, through which it runs.^[5] Service is managed by the San Joaquin Regional Rail Commission, and operations are contracted to Herzog Transit Services.^[5] The 86-mile (138 km) route includes ten stops, with travel time about 2 hours and 12 minutes end-to-end. In 2023, the line had a ridership of 576,300, or about 2,500 per weekday as of the fourth quarter of 2023. ACE uses Bombardier BiLevel Coaches, MPI F40PH-3C locomotives, and Siemens Charger 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. Saturday service commenced in September 2019. As of 2018^[update], average weekday ridership was 5,900.^[6]

The tracks are owned by Union Pacific Railroad, previously built along the Western Pacific Railroad main line. 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.

^ "Transit Ridership Report Fourth Quarter 2023" (PDF). American Public Transportation Association. March 4, 2024. Retrieved March 14, 2024.
^ "Transit Ridership Report Fourth Quarter 2023" (PDF). American Public Transportation Association. March 4, 2024. Retrieved March 14, 2024.
^ Cite error: The named reference acehistory was invoked but never defined (see the help page).
^ "AAR Railroad Reporting Marks (2015)". Railserve. Retrieved June 28, 2016.
^ ^a ^b Solomon, Brian (2013). North American Railroad Family Trees : An Infographic History of the Industry's Mergers and Evolution. Minneapolis, MN: Voyageur Press. p. 127. ISBN 978-0-7603-4488-0.
^ "Transit Ridership Report: Second Quarter 2018" (PDF). American Public Transportation Association. August 24, 2018. Archived from the original (PDF) on October 4, 2018. Retrieved December 6, 2018.

[APTAdaily-1] "Transit Ridership Report Fourth Quarter 2023" (PDF). American Public Transportation Association. March 4, 2024. Retrieved March 14, 2024.

[APTA_Ridership_Report-2] "Transit Ridership Report Fourth Quarter 2023" (PDF). American Public Transportation Association. March 4, 2024. Retrieved March 14, 2024.

[acehistory-3] Cite error: The named reference acehistory was invoked but never defined (see the help page).

[RailServe-4] "AAR Railroad Reporting Marks (2015)". Railserve. Retrieved June 28, 2016.

[Solomon_2013-5] Solomon, Brian (2013). North American Railroad Family Trees : An Infographic History of the Industry's Mergers and Evolution. Minneapolis, MN: Voyageur Press. p. 127. ISBN 978-0-7603-4488-0.

[apta-6] "Transit Ridership Report: Second Quarter 2018" (PDF). American Public Transportation Association. August 24, 2018. Archived from the original (PDF) on October 4, 2018. Retrieved December 6, 2018.

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