A rebirth of the long-ago rail route between Philadelphia and the Lehigh Valley is among the possibilities being considered in a two-year study looking at transportation options for the quickly growing region.

The MoveLV: Long Range Transportation Plan will look for the best transportation options for the Allentown-Easton-Bethlehem region. Surveys conducted in the last year suggest demand for such a major rail project.

"One of the top things that always comes up is rail service," said Becky Bradley, the Lehigh Valley Planning Commission's executive director.

The study will estimate the costs of rail service to Philadelphia and recommend who might operate it. Even if rail is determined a viable option, it would be a decade or two before trains start running again. The study will look at a range of transportation options, Bradley said, including a rail line to New York and expanded bus service in the region and to Philadelphia and New York.

Obstacles abound for a rail line to Philadelphia. Federal funding for transportation has declined to a trickle, said Chris Puchalsky, of the Delaware Valley Regional Planning Commission, and much state money is wrapped up in maintaining existing rail networks.

"We're not in the funding environment where this is feasible today," he said of restarting rail service from the Lehigh Valley to Philadelphia.

The project could require creative funding, Bradley said, including partnerships between private and public entities.

Another problem is that the rights of way that had hosted rail service between Philadelphia and Lehigh Valley decades ago are now occupied by a different form of transportation, "a very popular [bike] trail to a very well-moneyed group of residents," Bradley said.

Rail travel between the city and the region encompassing Allentown, Easton, and Bethlehem has been absent since the 1980s. Interest in resuming it has increased because the region, while revitalizing, is also facing growing pains.

About 650,000 people live in the region, Bradley said. She estimated that the population will increase to 875,000 by 2040.

"We've seen significant congestion on our roads," she said.

What's more, about 18,000 people from Montgomery and Bucks Counties commute to work in Lehigh or Northampton Counties, according to census data. Also, Philadelphia and Montgomery and Bucks County employers draw about 19,000 workers from Lehigh County and 11,000 from Northampton County.

If it happens, a Lehigh Valley-Philadelphia area rail line could be an economic boom for both regions, Puchalsky said. In the Delaware Valley, it could bring much-needed development to such communities as Quakertown in Bucks County, he said.

"It's certainly a valuable study to undertake for the future," he said, "but I think people should understand some of the things that would need to fall in place for it to happen."