The Northeast Corridor has long been considered as offering the most practical route for introducing the U.S. to high-speed rail (or something close to it, anyway). Though many infrastructure obstacles must yet be overcome before those futuristic sleek trains routinely cruise the 453 miles between DC and Boston, the Baltimore and Potomac Tunnel may soon be removed from that list.

“Soon,” of course, could mean in a decade or two given the myriad technical issues that will need to be hammered out, plus the limitations of transportation funding. But a new engineering and environmental impact study underway may well be the first step toward eliminating a 1.4-mile masonry relic of the 1870s that has cramped both the speed and volume of the region’s passenger and freight traffic for decades.

The $60 million study, being conducted by Parsons Transportation Group for Amtrak, the tunnel’s owner, will assess alternatives to the double-tracked serpentine tunnel and its longstanding constraints—a sharp curve that limits speeds to 30 mph, low height that prevents use by increasingly popular double-stacked container cars, and a relatively steep uphill grade that can make many northbound trains have to emulate the “I think I can” mentality of The Little Engine that Could.

The tunnel’s chokepoint characteristics are difficult enough when train traffic is moving smoothly. But even little problems can have a huge ripple effect up and down the Eastern Seaboard, as was demonstrated earlier in November when an Amtrak locomotive slipped off the tracks.

As for the potential of big problems, consider the weeklong closure caused by a 2001 tanker train derailment and fire inside another Baltimore tunnel. Anything close to a similar occurrence in the Amtrak tunnel would no doubt have potentially worse consequences, particularly with as Amtrak and the Maryland Transit Administration's MARC commuter rail system seek to ramp up service to nearly double the systems’ combined 145 trains that navigate the tunnel every day.

And considering that the Port of Baltimore wants to streamline its multi-modal cargo connections to lure post-Panamax shipping traffic, it’s clear that the 19th Century tunnel is simply not up to the job of handling large volumes of 21st Century rail traffic.

The solution won’t be easy or inexpensive. Amtrak’s working concept of two bored tunnels deep beneath the city carries a current pricetag of $1.5 billion. That sounds like a lot of money, and it is.

Compared with the opportunity costs of improved safety and reliability for a substantially greater volume of higher speed rail traffic, however, anything close to that figure might well prove to be a worthwhile investment in finally building some momentum for Northeast Corridor’s high-speed rail dreams.