SPUR’s report Critical Cooling recommends 42 options for reducing local carbon emissions. This is one of them. To learn about all 42 ideas, read the full report

Caltrain Electrification

Urbanist Article
Annual savings potential:
Annual public cost:
Public cost per ton:
Implementing agency:
Horizon year:
48,800 tons
Caltrain Joint Powers Board


  • 6,200 metric tons of emissions abatement will result from the decrease in auto travel as a result of faster, more reliable transit service.
  • Almost 42,000 tons of emissions abatement will result from reduced energy consumption by Caltrain.


Electrifying Caltrain would benefit commuters by providing somewhat faster service. This improvement would yield a significant increase in ridership. In addition, electrified trains would consume less propulsion energy, yielding a large decrease in emissions. The majority of this abatement would result from reduced energy consumption. The remainder would result from reduced auto travel resulting from more commuters choosing Caltrain. However, the combined benefits do not yield enough emissions abatement to justify the capital investment on the basis of emissions alone.

Relative Impact
There will be 145.93 million daily vehicle miles traveled in the Caltrain corridor by 2030, generating approximately 15.54 metric tons of CO2 emissions per year.1 The total existing CO2 emissions from Caltrain operations is an estimated 58,000 metric tons per year.2

What we do now
Caltrain provides commuter rail service from Gilroy to Fourth and King streets in downtown San Francisco. These trains are propelled by diesel-powered locomotives. The train service is operated but the Peninsula Corridor Joint Powers Board, which is a partnership between the municipalities along the San Francisco Peninsula. Caltrain has significantly increased its ridership in recent years, particularly after the introduction of “baby bullet” service, which offers commuters a rapid, skip-stop commuter service.


What we could do
Part of Caltrains long-term capital improvement vision is a plan to electrify its train service, switching from trains propelled by diesel locomotives to electric multiple unit trains. Electrification would have two benefits for CO2 emissions. First, EMU trains can accelerate and decelerate faster than diesel-powered trains, resulting in improved travel times. Second, EMUs would consume significantly less energy for propulsion than diesel locomotives, reducing emissions.


The electrification program would require significant new capital investments for new rolling stock, overhead wire, and associated facilities. Caltrain most recently estimated the cost of its electrification program in its Caltrain 2025 vision. In that document, it estimated that transitioning to non-compliant EMU trains would add an additional $34.23 million to the organization’s costs by 2025, including both the life cycle cost of equipment and well as operations and maintenance.3

Carbon savings potential
Electrification of the Caltrain corridor will reduce emissions by a total of 48,800 metric tons per year. The majority of this abatement, 42,500 metric tons, would result from reduced energy consumption. The remainder, 6,200 metric tons, would result from reduced auto travel resulting from more commuters choosing Caltrain. The cost of emissions abatement would be $700 per metric ton.


1 Downtown Transit Center FEIS
2 Caltrain Electrification EIR chapter 3
3 Caltrain 2025.