BART is already being extended to Livermore (just west of the Altamont pass), and already goes to Dublin, so that area is at least already well-served by regional transit.
Going over the Pacheco Pass allows the train to hit San Jose and the Silicon Valley without going through huge windy detours, which has a lot more people in it than the Altamont Pass area.
Going over the Pacheco Pass allows the train to hit San Jose and the Silicon Valley without going through huge windy detours, which has a lot more people in it than the Altamont Pass area.