That's an interesting paper. Thanks.

One issue with it, though, is cost and scale. The LAUS Run-Through Tracks are an excellent example of something that fits the paper's concept. A new Bay Tube from Salesforce to someplace in the East Bay is not. The basic concept promoted in the paper is a relatively short connection between existing lines that allows operating improvements by letting trains run through rather than terminating at downtown stations.

On the surface, the Bay Tube might seem like that, but it isn't, really. There's no real terminal or suburban service in the East Bay that it would connect with. BART already provides that service. Really, it's the major piece of a new High(er) Speed intercity line that, in combination with a new, high-level Benecia Bridge and other improvements for the Capitol Corridor, would provide a modern passenger trunk line between the Central Bay Area and Sacramento (~110 mph). That's a worthwhile project, but if we can't afford to, say, extend the Valley HSR segment to Palmdale or LA, we can't afford the New Tube either. Most likely similar orders of magnitude for cost and complexity. And extended delivery time.