Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 38. Chapters: Railroad bridges in Maryland, Railroad roundhouses in Maryland, Railroad tunnels in Maryland, Railway stations in Maryland, Northeast Corridor, Old Main Line Subdivision, Capital Subdivision, Baltimore Belt Line, Thomas Viaduct, Metropolitan Subdivision, Bollman Truss Railroad Bridge, Baltimore Terminal Subdivision, Amtrak Susquehanna River Bridge, Baltimore and Potomac Tunnel, Carrollton Viaduct, Silver Spring, Pope's Creek Subdivision, Philadelphia Subdivision, Gaithersburg, Laurel, Kensington, Frederick Branch, Hanover Subdivision, National Gateway, Point of Rocks, Keystone Subdivision, Landover Subdivision, Lurgan Branch, Patterson Viaduct, Crescent Corridor, Stickpile Tunnel, Indigo Tunnel, Perryville, Kessler Tunnel, Mountain Subdivision, Lurgan Subdivision, Rockville Railroad Station, Brush Tunnel, Cumberland Subdivision, Odenton, Brunswick, West Baltimore, Henryton Tunnel, Cumberland Terminal Subdivision, Halethorpe, Perryville Railroad Bridge, St. Denis, Union Tunnel, Savage, Bowie State, Borden Tunnel, Monocacy, Laurel Race Track, Bloomington Viaduct, Dorsey, Martin State Airport, Washington Grove, Riverdale, Dickerson, Edgewood, Chestertown Railroad Station, Patterson Creek Cutoff, Boyds, Muirkirk, Barnesville, Germantown, Metropolitan Grove, Garrett Park, Sand Patch Grade, Jessup, Fairmont Subdivision, Dalecarlia Tunnel, Hagerstown Roundhouse Museum. Excerpt: The Northeast Corridor (commonly abbreviated NEC) is the busiest passenger rail line in the United States by ridership and service frequency. The route is fully electrified and serves a densely urbanized string of cities from Washington, D.C. to Boston, including Baltimore, Wilmington, Philadelphia, Trenton, Newark, New York, New Haven, and Providence. It also has branches connecting Philadelphia with Harrisburg, Pennsylvania (known as the Keystone ...