It's my understanding that the electrification of the segment between Tamien Station and Gilroy is still under negotiation and planning as of this year. 

Source: https://hsr.ca.gov/wp-content/uploads/2024/02/2024-Draft-Business-Plan-020724-A11Y.pdf
"The Authority's plans for the corridor would add electrified passenger rail tracks for highspeed rail and Caltrain service, while maintaining and improving the freight infrastructure for Union Pacific to serve its customers. In 2024, the Authority will continue to engage with Union Pacific to advance the necessary agreements for use of the corridor."