Caltrain’s Green Rail: California’s Regenerative Braking Revenue Boost
Caltrain’s new electric trains will generate revenue through **regenerative braking**, earning $1 million annually. This innovative step in **railway** operations supports electrification and clean energy goals.

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Introduction
Following policy changes by its renewable energy partners, Caltrain will begin receiving payments for the clean electricity its new electric trains return to the grid through regenerative braking. This initiative, representing a first-of-its-kind policy for public transport in California, will allow Caltrain to earn around USD 1 million annually starting in April 2026.
Net Billing Agreement
Under the new agreement, Caltrain will qualify for a Net Billing Rate starting in April 2026. This will allow the operator to earn around USD 1 million annually for the energy it supplies to the grid. Caltrain currently feeds back about 23% of the electricity it consumes into the power grid, providing emission-free energy to homes and businesses along its corridor.
Legislative Alignment
The policy change aligns with Assembly Bill 1372, authored by Assemblymember Diane Papan, which recognises regenerative braking from electric trains as a renewable electricity generation source. The bill would require energy providers to compensate rail operators for the power they return to the grid. Once the bill takes effect, Caltrain could receive a further 20% in compensation from its energy distributor PG&E, in addition to the revenues enabled by the policy changes.
Financial and Operational Impact
Originally projected to cost USD 19.5 million per year, Caltrain’s electricity expenses have been revised downward to USD 15.3 million. This revision is based on current average energy consumption of 207 MWh on weekdays and 175 MWh on weekends. The use of 100% renewable electricity also qualifies Caltrain for revenues under California’s Low Carbon Fuel Standard programme, further reducing overall energy costs.
Regenerative Braking Technology
Regenerative braking, first introduced to electric trains in 1886, works by running an electric motor in reverse, capturing energy that would otherwise be lost as heat. Caltrain’s new electric fleet is designed to feed this recovered power back into the Overhead Contact System (OCS), which then transfers it to nearby traction substations. The returned energy can either power other trains on the line or be fed directly back into the local grid, contributing to regional renewable energy supplies.
Conclusion
Caltrain will receive payments for the clean electricity its new electric trains return to the grid through regenerative braking, starting in April 2026. This will allow the operator to earn around USD 1 million annually for the energy it supplies to the grid, as part of a new Net Billing Rate agreement. The policy change is supported by Assembly Bill 1372 and aligns with the operator’s ongoing electrification program.
Company Summary
Caltrain: Caltrain operates passenger rail services in the San Francisco Bay Area. The company is transitioning to an all-electric fleet.
PG&E: PG&E is an energy distributor.
Technology
Overhead Contact System (OCS): The OCS is the system that supplies electricity to trains via overhead wires.
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