How, these critics wondered, could one of the world’s greatest universities — one that produced so many of the liberal intelligentsia who run the region — be so dead set against a big, bold, green idea like a light-rail line?

Advocates for the train insist that the proposed 17.7-mile service could combat gridlock by linking Durham and Chapel Hill, home to the University of North Carolina, and would provide access to three major hospitals, as well as the historically black North Carolina Central University in Durham.

They also envision the train as a social justice engine, offering cheap, reliable transportation to the working people who scrape by, cooking and cleaning for the legions of college students in the Research Triangle, the area that includes the two college towns and Raleigh, the state capital.

Indeed, in recent days, as the regional transit authority, GoTriangle, tried unsuccessfully to persuade Duke to donate land for the project, proponents emphasized the history of town-gown tensions between working people in Durham County — a majority-nonwhite community where 27 percent of children live in poverty — and an elite private institution that did not admit a black student until the early 1960s.

“Given the long history of fraught relations between many low-income Durham residents and Duke University, supporting the project would be a brilliant way for Duke to reassert its good will to the community,” said a letter to Vincent Price, the president of the university, that was signed by more than two dozen members of the university’s Nicholas School of the Environment faculty.

But Duke officials are adamant that their objections to the project are serious and insurmountable. They said construction vibration and electromagnetic interference from the trains might affect sensitive research equipment at Duke’s sprawling medical campus, which the train line would skirt. And they are concerned about the project’s impact on the underground utilities that serve the medical center — and the threat of new lawsuits.