ACE Moves to Sole Use of Renewable Diesel for Locomotive Fleet

November 28, 2022

ACE Moves to Sole Use of Renewable Diesel for Locomotive Fleet



David Lipari
(209) 851-1626

ACE Moves to Sole Use of Renewable Diesel for Locomotive Fleet

Stockton CA – As a part of its Climate Action Plan, San Joaquin Regional Rail Commission (SJRRC) has moved to the sole use of renewable diesel on its locomotive fleet for the ACE train service. The move to renewable diesel will reduce greenhouse gas emissions by 99%. ACE is Northern California’s first commuter rail service to switch to 100% renewable diesel operations. This step is a key milestone for the agency on its path to net zero emissions operations.

“We are proud to announce that ACE is operating with renewable diesel. Our commitment to reducing greenhouse gas emissions has taken a large step forward,” states Brian Schmidt, Director of Equipment Services at SJRRC. “Our fuel partner, Valley Pacific, has been a key partner in this transition.”

Renewable diesel is made from responsible and sustainable feedstock, such as used cooking oil and/or inedible corn oil. SJRRC is utilizing R100, indicating that the fuel is 100% renewable diesel. Fuel for the ACE fleet is supplied by Valley Pacific Petroleum Services, Inc. The ACE fleet utilizes 51,000 gallons of fuel per month.

“Our customers have found that, compared to petroleum-based diesel, renewable diesel works better in their engines, produces less ash, and they’re happy it improves air quality and lowers their carbon footprint,” states Nathan Crum, President & CEO of Valley Pacific.

SJRRC’s first step toward a cleaner fleet came in 2017 with the introduction of the Tier IV Siemens Charger Locomotives which have replaced Tier 0 locomotives in the active fleet. The Siemens Charger Locomotives provide a minor increase in GHG emissions but a substantial improvement in air quality emissions. These locomotives also allow an increase in coaches per train (from 7 to 10), which improves per-passenger fuel efficiency metrics. A key factor in the switch to renewable diesel was to ensure the Cummins engine would continue successful operation with the introduction of a new fuel type. Through a series of testing and discussions, the engine manufacturer Cummins has approved 100% renewable diesel for use in their engines used in the Siemens Charger locomotives and poses no harm to the engine or its components.

SJRRC’s Climate Action Plan includes several steps to reaching a net zero operation. In addition to the switch to renewable diesel, SJRRC is launching a research and development project exploring zero-emission locomotives. A key factor in this research is to identify and study a method zero-emission propulsion method that can handle the grades in the Altamont Pass. Other components of the Climate Action Plan include: converting connecting shuttle/bus services to electric vehicles and on-site solar programs for stations. In its role as the managing agency of the San Joaquin Joint Powers Authority (SJJPA), SJRRC is working toward switching the San Joaquins trains and Thruway Buses to renewable diesel.


Governed by a Board of Directors consisting of six full-voting members from San Joaquin County and two special-voting members from Alameda County, SJRRC owns, operates, and is the policy-making body for the Altamont Corridor Express (ACE) service, which has been transporting passengers between the Central Valley and Bay Area since 1998. For more information about SJRRC and ACE, visit or connect through Facebook (@AltamontCorridorExpress) and Twitter (@ACE_train).

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