In November 2020 California voters passed Measure RR to fund electrification of Caltrain down the San Francisco Peninsula. After several years of construction, the new electrified trains entered service on September 21, 2024: exactly one year ago at the time of this writing.
The electrification measure was an audacious plan for Caltrain to recover from the Covid-driven disruption in travel patterns by radically improving the service. The electrified fleet would provide more frequent service because the new engines would accelerate and decelerate far more strongly than the diesel locomotives did. The rolling stock would additionally be refreshed with new passenger cars.
So: did it work? Based on ridership data from the last year, to me it certainly appears so.
The large drop in ridership in 2020 is due to Covid. I tried to show the slope by drawing red lines in the few years between Covid and electrification, and between electrification and now. The rate of increase in ridership changed markedly for the better in almost exactly 9/2024 when the lines were electrified.
Ridership has not yet returned to pre-Covid levels, but now appears to be on track to do so if trends continue.