The Fredericksburg Line is the longer, higher ridership, and more scenic VRE Line. It is one month younger than the Manassas Line, opening on July 20, 1992. The line operates 54 miles from Washington, DC through Fredericksburg (its opening day terminus of passenger service) to Spotsylvania where service was extended the five miles on November 16, 2015. This station you could argue was an infill station because all trains already deadheaded south to the Crossroads Yard located just beyond this new station. Two additional infill stations also opened on the line in Lorton and Franconia-Springfield in 1995.

The Fredericksburg Line operates along the extremely busy Richmond, Fredericksburg, and Potomac Railroad, a 'bridge railroad' that connects railroads (now pretty much all controlled by CSX) in the south with northern railroads in Washington, DC. The frequent freight traffic along this line, although it is two tracks, means that trains only operate during rush hours in the peak direction only. As of mid-2025 Eight northbound trains depart Spotsylvania between 4:52am (the first train of the morning is an express skipping four stops) and 7:46am. Eight Southbound trains depart Union Station at 1:00pm (an early afternoon train) and between 2:40pm and 6:50pm.

Amtrak's Northeast Regional trains to Richmond, Newport News, and Norfolk provides supplemental service along the Fredericksburg Line with trains stopping at five of the line's 13 stations. The stations Amtrak doesn't stop at (except for Franconia-Springfield that Amtrak did stop at from 2003 and 2010) only contain a platform on the eastern track. This was done to save on costs when the Virginia Railway Express was being built. The line is also used by the Plametto, Floridian (these trains run non-stop from Alexandria to Richmond), Carolinian and Silver Meteor. Amtrak's AutoTrain also shares tracks with VRE from its Lorton Terminal, (a mile-ish south of the VRE station with the same name) southward.

The reason to ride VRE on the line instead of Amtrak in addition to tickets generally but not always, if you book Amtrak in advance, being cheaper is the fact the Gallery IV Cars of VRE have amazing large and generally kept spotlessly clean windows. These windows a small Amfleet I or even slightly larger Amfleet II of the longer distance trains can't be competed with. The views along the Fredericksburg Line are quite scenic in places as the line follows the extremely wide Potamic River, crossing bridges over tributaries of it. There isn't very much urban development around many of the stations except for Lorton (with a modern town center development), and the historical centers around the Quantico and Fredericksburg Stations that Amtrak has always served and pre-date VRE.

I have not ridden or visited every station on the Fredericksburg Line. The two stations I'm missing are Spotsylvania and Quantico both for real, but very different reasons. The Spotsylvania Station has a few modern apartments around it in the giant over 1,000 space parking lot, but no hotels, and no connecting public transit since it looks like the nearest bus stop is two miles away along roads that don't look very safe for walking. The Quantico Station is at a regular American Town completely surrounded by a Marine Base. Passengers wanting to drive onto the base to use the station need to visit a Visitors Center and register to get a permit. It is unclear to me if a passenger can exclusively visit the station getting off a train, visiting one of the restaurants for example (I found a tempting looking breakfast place online), and then get back on the next train without approval from the Marines.

Technically I haven't ridden every inch of VRE, since I'm missing the switch onto the spur into the Spotsylvania station. Spotsylvania is visible from passing Amtrak trains.