Today’s American railroads are the products of hundreds of mergers and combinations of earlier lines, so it’s a good bet that there’s a good story behind any particular stretch of track. Here’s the tangled tale of the route followed by Amtrak’s Northeast Corridor trains as they head south from Philadelphia’s 30th Street Station.

(And if you’re intrigued by that 15-foot marble obelisk, click through for the whole fascinating story of the 1839 Newkirk Monument.)