Maryland residents would be able to ride MARC commuter trains to jobs in Northern Virginia under legislation being introduced in the General Assembly this week.

The bill directs the state to begin laying the groundwork that would allow MARC trains to travel past Union Station in the District and into Virginia, with the goal of having the Maryland commuter rail service operating across the Potomac River within a few years.

“Most commuters, certainly the people who work in Northern Virginia, would love to get on a train and know that it goes straight into Northern Virginia,” said Maryland Del. Jared Solomon (D-Montgomery), the lead sponsor of the legislation.

Under the proposal, the Maryland Department of Transportation would be required to enter negotiations with the District, Virginia and the railroads that use and own the tracks south of Union Station to allow MARC trains to carry passengers into parts of Arlington and Alexandria. The move is in anticipation of an influx of development and jobs in across the Potomac River — namely the arrival of Amazon’s second headquarters in Crystal City.

Marylanders would benefit from having a one-seat ride to jobs sites in Northern Virginia, Solomon said, even before the anticipated expansion of Long Bridge, which connects the District and Virginia, and is being expanded to double capacity for train traffic over the Potomac.

The legislation urges MDOT to “engage in good faith negotiations” and reach a written agreement on a pilot program to have MARC trains sharing the tracks with the Virginia Railway Express to serve L’Enfant Plaza, Crystal City and Alexandria.

The proposed pilot would include two southbound trips in the morning and two northbound trips in the evening. MDOT would be required to report to the General Assembly on the ongoing negotiations and “identify solutions to any impediments” to carry out the plan. The bill has bipartisan support, is co-sponsored by at least two dozen legislators, and it is backed by the transit caucus and some business groups.

The idea of Maryland and Virginia commuter trains crossing jurisdictional lines has been discussed for decades but has recently picked up momentum as critical rail investments are planned over and south of the Potomac.

The Metropolitan Washington Council of Governments is conducting a market ridership study for MARC and VRE run-through service to assess potential ridership and identify critical elements that would need to be addressed before service begins. Early findings are expected in the next few months.

Solomon said he anticipates it would take the state a couple of years to assess the feasibility, cost and operational issues that would need to be addressed for the service plan, with a pilot potentially in place in five years.

There may also be some technical and regulatory issues Maryland would need to navigate for example, the platform height differences at MARC and VRE stations. But some transportation experts familiar with the conversations so far say the infrastructure and equipment differences are not a problem and that there are open slots to accommodate Maryland trains.

“The bill is an important step to answering what we can do in the near term and make that a reality,” said Joe McAndrew, director of transportation policy at the Greater Washington Partnership, a group of corporate leaders pushing for better integration of the region’s commuter train service.

The change, McAndrew said, would allow companies like Amazon to have access to a larger pool of job candidates with an easy transportation option. Suburban Maryland residents would have an easy train ride to jobs in areas like Crystal City, soon to be home to 25,000 new jobs at Amazon’s second headquarters. Today, for example, anyone coming fromKensington on MARC’s Brunswick line would need to transfer at Union Station to Metro’s Red Line and then to the Yellow Line at Gallery Place to get to Crystal City. (Amazon founder Jeff Bezos owns The Post.)

Besides Amazon, Crystal City and nearby Alexandria are expected to boom with retail, housing, and job and educational opportunities. Virginia Tech, for example, is building a new Innovation Campus at Potomac Yard.

Andrew VanHorn, executive vice president at JBG Smith, which owns most of Crystal City and is preparing space for Amazon, said the company “strongly supports” extending MARC service to the area and Solomon’s leadership to make it happen.

“Thru-running of MARC trains would provide thousands of MARC riders a ‘one-seat ride’ to one of the region’s most dynamic job centers, while helping to ease pressure on the Metro system and road network,” VanHorn said in an email. “At the same time, it would broaden the housing options for area workers and enable employers to access a larger talent pool in their recruiting efforts. Such expanded service is a key component of a larger vision, which was recently advanced by Virginia’s landmark agreement with CSX, to expand passenger rail in the region.”

Virginia last month announced a $3.7 billion deal with CSX that includes the construction of a rail bridge next to the Long Bridge, doubling capacity at the crossing. The Long Bridge expansion is viewed as a critical piece to making run-through service possible.

A plan for the Long Bridge, which carries 76 trains on a typical weekday — nearly half with Northern Virginia commuters headed into the District — estimates the number of trains to increase significantly by 2040. The number of VRE trains is expected to grow to 92 from 34, Amtrak’s daily trips could grow to 44 trains from 24, and MARC could add eight trains into Virginia.

Solomon said Marylanders don't have to wait until the Long Bridge is completed to begin to test the benefits of such an extension. And, he said, he also expects the same opportunity for Northern Virginia residents to travel to jobs in Maryland.

“It is so critical that people have a way to get to and from Northern Virginia and to and from the Maryland suburbs without having to drive,” Solomon said. “The more options that we can present to people that don’t necessarily revolve around driving, the better.”