A few small problems with the ex-SP Altamont Pass / Niles Canyon line: it was engineered in the 1860's and has lots of curves that seriously impact train speeds. By comparison, the former WP (now UP) line was engineered in the early 1900's and had better alignments and grades. And when SP pulled up the line through Livermore and Pleasanton, developers promptly moved in and built right up to the old grade so there is NO WAY IN HELL that tracks will EVER get put back in place. Add to that the increased populations in both cities and you wind up with an impossible NIMBY situation. The best ACE could ever do is build a parallel track next to the existing UP line through the valley.

If the $$$$ are found, maybe (?) the original SP line through Niles Canyon could be re-engineered to support higher train speeds (anybody recall what SP's train speeds were on that line? My guess is 25 - 30 mph for everything.) but that would involve a lot of political yelling and screaming from all the environmental types. Not a good propect. On the other hand, the UP line has several tunnels that kill the idea of adding a second track there, so....?