Preparations for the construction work needed to electrify Caltrain along the Peninsula corridor have started and will last until the end of February, officials with the transit agency said Thursday.
Workers will be locating utilities, testing soils and testing cables, primarily during the day but sometimes overnight between 8 p.m. and 6 a.m.
Caltrain officials said residents living nearby should have received a notice about the work.
Passengers should be aware of signs indicating they need to board from a different platform because at time trains may share one track.
The work is part of the overall Peninsula Corridor Electrification Project, which will electrify the Caltrain system from Fourth and King streets in San Francisco south to about the Tamien Caltrain Station in San Jose.
The aim of the project is to reduce carbon emissions, reduce noise and improve regional air quality, according to Caltrain officials.
Construction itself is expected to start in the spring or summer of next year and the project is expected to be complete at the end of 2020 or the beginning of 2021.
The operating speed of the trains will not change but the number of trains in service will increase overall, Caltrain officials said.