His proposal makes a lot of sense as the BART right-of-way is already established between Fremont and San Jose. Also the BART link to San Francisco from Fremont already exists as rapid transit.
Here is my two cents. Upgrading Caltrain by electrification can be done with battery powered trains. The Peninsula train tracks could be left alone. This would not require any right-of-way costs but would require purchase of new railroad cars and a battery charging system in San Jose and San Francisco.
Jerry Secrest, Willowbrook Drive, Portola Valley