Sen. John Kerry, D-Mass., plans to introduce a $1 billion spending bill designed to modernize bridges and tunnels along the Acela route from Washington to Boston, allowing the high-speed train to reach its promised speed of 150 mph. "You know why it can't go 150 under Baltimore? Because it shakes the tunnel and it's unsafe for the city. You can't go over the bridges because they're unsafe because we haven't rebuilt them for high speed." An Amtrak spokesperson, however, said upgraded bridges and tunnels would speed the train by only about 15 mph, because curved tracks through the heavily developed Northeast corridor are the main reason for the slow ride.