Passenger rail with zero emissions

Moving toward increased connectivity and zero emissions passenger rail in California

The San Bernardino County Transportation Authority (SBCTA) sought out to expand its public transit network in southern California and reduce greenhouse gas emissions by replacing the diesel vehicles with zero emissions multiple units (ZEMUs) as a follow-on project to the Redlands Passenger Rail project.

Development and implementation of a hydrogen train

On behalf of the SBCTA, we prepared a grant application that won $30 million initially and $15.8 million subsequently from the California Transit and Intercity Rail Capital Program. The funds were allocated for research, development, and implementation of a ZEMU vehicle, the supporting infrastructure, and eventually the conversion of the existing diesel multiple unit (DMU) vehicles.

We then evaluated zero emissions technologies including alternative fuels, batteries, hydrogen fuel cells, and hybrids. In July 2019, the SBCTA’s board unanimously approved the implementation of a hydrogen fuel cell and battery hybrid vehicle.

Our team then supported the SBCTA by overseeing pilot vehicle testing, commissioning, and regulatory approval with the Federal Railroad Administration.

Designing hydrogen fueling and maintenance facilities with safety at the forefront

The Mott MacDonald team led the design, procurement, and implementation of the supporting hydrogen fueling infrastructure, upgrades to the Arrow Maintenance Facility (AMF), and worked with local agencies to obtain permits.

Members of the ZEMU project team and the Federal Railroad Administration (FRA) in an Arrow Maintenance Facility

The ZEMU vehicles will be maintained in the existing AMF building, which is currently used for diesel vehicle maintenance. We led the evaluation of the AMF building conditions to identify necessary modifications to meet hydrogen code requirements. Working closely with members of the Hydrogen Safety Panel, the team completed a code analysis to determine how to retrofit the facility to address hydrogen specific hazards. We also completed computational fluid dynamic modeling to support the application of the codes and define additional classification zones within the facility.

An industry first in North America

The ZEMU vehicle will be the first federally-compliant hydrogen fuel cell-battery hybrid passenger train operating in North America. Testing and commissioning of the vehicle is complete with a target date of operations in May of 2025. The ZEMU vehicle fueling and maintenance facilities will also be the first of their kind in North America. The zero emissions train will improve air quality in the region and demonstrate the potential greenhouse gas reductions and other benefits that this technology could offer throughout California and the US. Following the success of this project, California Department of Transportation (Caltrans) announced the purchase of another thirteen ZEMU vehicles to deploy throughout California in 2027.