The freight train derailment in the Bronx that blocked Amtrak service yesterday and is causing problems even today was bad (Boston-bound passengers had to take shuttle buses from Penn Station to Grand Central, then take the Metro-North to New Haven to pick up an Amtrak there - totally sucks), but Gothamist is a little more freaked out about why PATH service was held up during last night's commute: A building with a sagging wall. The Post reports that the Department of Buildings found that 500 Hudson Street had a 3% bulge, and asked the Port Authority to stop PATH service because the vibrations from the train might cause further instability. The DoB said that renovation work there was causing the problems, but new work or not, being reminded that train service could cause buildings to collapse is an "Oops, I Crapped My Pants" moment.