For the third time in city history, the New Haven Department of Transportation is considering the revival of a trolley program to run between Union Station, downtown New Haven and some surrounding areas.

Projections by two national consulting companies, URS and TranSystems, have shown that the project would take 10 years and $30 million to finance, build and operate, and would likely connect Union Station to City Hall, Yale’s campus, the theater district and Yale-New Hospital via a 3.6-mile-long track. Though the previous trolley program — the historic green and red fleet of retrofitted buses — closed this past October, Director of New Haven’s Department of Transportation, Traffic & Parking Mike Piscitelli lauded the new proposal as a worthy long-term investment.

“We are very optimistic on this,” Piscitelli said in a Monday interview. “The TranSystems report did a good screen of our options, orders of magnitude and cost, and this is all within a feasible, programmed, measured approach.”

But Elihu Rubin, a professor of urbanism at the Yale School of Architecture, raised a concern: “I love trolleys,” he said, “but is the answer to take on a major capital investment campaign to reinstate them?”

He added: “The trolley has to be more than a gimmick.”

Piscitelli said he is currently awaiting word from URS, a San Francisco–based consulting firm, in response to questions posed by his department during a Feb. 10 workshop on the project’s viability. The meeting, which included representatives from both the city and from Yale, ended with optimism, Piscitelli said Monday. He avoided comparisons to the previous trolley system, which the city shut down when funding ran out and profits dried up.

And with the city having recently laid off dozens of employees and currently struggling to balance the 2009-’10 budget, Piscitelli said he will keep an eye on the bottom line. He explained that public buses tend to be less expensive to own and operate than electric trolleys. New Haven, indeed, hopes to receive federal funding for the proposed trolley project. Programs such as the Federal Transit Administration’s “Small Starts” program provide grants for the capital costs associated with new fixed-path transportation systems, but programs eligible for the grant must cost between $25 million and $250 million.

“So when you’re looking at federal funds,” he said, “you have to be able to do a cost-benefit analysis based on their analytical approach.”

The city is not fully accepting either report at face value, as no formal plans are yet in place to move forward with either firm’s proposals. One of the differences between the TranSystems recommendation and the city’s current plan of action is that TranSystems advocates a single route, whereas the city plans to compare four different routes before making a final decision. So far, URS has provided Piscitelli’s office with “background material, not the final material,” Piscitelli said. The word is still out, then, on whether New Haven streets are wide enough to support trolleys as well as automobile traffic, or if the streets are free from utilities hidden underground that would hamper development. This information is expected from the forthcoming URS report.

Rubin said that as a “trolley buff,” he is enthusiastic about the proposal — with some reservations.

“Planners and politicians today have come around to fixed-rail transit not only because it is increasingly associated with ‘modernity’ and ‘improvement’ and ‘progress,’ ” he wrote in an e-mail, “but because trolley stations can help anchor neighborhoods and local commercial districts. But good design for buses can do the same.”

The city sees a daily bus ridership of 25,000 to 30,000, Piscitelli said, though he declined to speculate on the potential ridership of the trolley system. The trolley, he added, would not be marketed to compete with the public bus system.

Across the globe, streetcars have brought zero-emission transportation to cities not unlike New Haven, but previous attempts by Elm City government to provide clean, affordable and healthy public transit options have seen mixed results. The model of trolley under consideration would have steel wheels running on fixed rails and receive electric-power from overhead wires. Although cities such as Portland, Ore., and Krakow, Poland, opted for a modern design to their trolleys, New Haven and its consulting firm favor the “heritage” or “historic replication” aesthetic that can be seen at the East Haven Trolley Museum.

According to a report by California research initiative “Better Transit,” a switch from diesel-powered buses to electric trolleys offers sustainability, health benefits and noise reduction.

David Schlussel ’11, the editor of forthcoming sustainability journal “The Wheel,” echoed these attributes of the trolley system, pointing out that in addition to public health, urban culture and business development, a trolley system would reduce car congestion and accidents.

It would also, he wrote in an e-mail, “make New Haven’s streets a friendly place for walking and biking.”

The URS report is the second on streetcars that the city has sought within a year. The first, “New Haven Electric Streetcar A Catalyst for Development,” came last spring from TranSystems at a cost of $150,000 — which the state subsidized. The city paid $20,000 for that report and $10,000 for the one from URS this winter.