I do wonder how dependent they are on the grid. PG&E, the utility in the area, will shut down power transmission in areas where there is high fire danger, blacking or browning out large parts of their service area. Since they were found responsible for the deadly Camp Fire that wiped our Paradise, CA a few years ago, regulators are closely watching them and they are quick to shut off transmission now.Airos are really not well suited for providing high average speed frequent suburban service with frequent stops. Airos are fine for NEC style regional service with less frequent stops, but they would be somewhat similar to NJT's heavy commuter trains that poke along a slow average speeds on a frequent stop suburban service.
Caltrain could have opted for electro-diesel dual mode EDMUs if they thought it was an important consideration, but they did not so choose. Clearly they are unlikely to retain a large fleet of F40s in serviceable condition continuously (it costs a lot of money to do so) to address an issue they chose not to address in the type of equipment they ordered.