David Zetland sent me this writeup on a plan I had not heard of -- apparently Amtrak has a $150 billion plan to improve speeds on the northeast corridor
Take, for example, Amtrak's proposal to bore a 10-mile rail tunnel underneath Philadelphia. As Steve Stofka, a transport blogger, explains, this proposal would require the most expensive type of tunnel imaginable—"It is freaking expensive to bore a ten-mile-long tunnel through an alluvial floodplain under a highly urbanised area—and to maintain it, since it will reside below the water table," Mr Stofka writes. At $10 billion, he notes that the project would be about three times as expensive per mile as the Gotthard Base Tunnel under the Swiss Alps. And all this is for marginal improvements in speed and access. The tracks around and through Philadelphia aren't, generally, big obstacles to high-speed rail—the tunnels in and around Baltimore, Maryland are. It would be much cheaper to replace Baltimore's terrible tunnels than to build a fancy new one under Philadelphia.
The Philadelphia tunnel, unfortunately, isn't even the worst part of Amtrak's plan. That honour goes to a $7 billion renovation of Washington's Union Station (pictured), which Slate's Matthew Yglesias rightly calls"insane".