By George P. Hassett

With the Green Line’s expected arrival in Somerville running three years behind schedule, aldermen this week proposed adding a temporary commuter rail stop in Ball Square to ease traffic and improve transit options for city residents. Currently two commuter rail lines run through Somerville yet neither stops in the city.

At Thursday’s Board of Aldermen meeting Ward 5 Alderman Sean T. O’Donovan suggested at least one rail line have a stop in the city until the oft-delayed Green Line extension through Somerville is completed. The $600 million Green Line project is scheduled to be finished by 2014.

“I watch the [commuter rail] zip through Ball Square everyday. Why not put a stop there until we get the Green Line?” he said.

The hopes for a Green Line extension through the city have been boosted in recent months by Gov. Deval Patrick’s visit to Gilman Square in October when he promised to try and complete the project before 2014 and in November when he included full funding of the project in his transportation bond bill.

Before that the project had an almost two-decade history of delays. In 1990, state officials promised Somerville residents they would complete a Green Line extension through the city as a way to offset air pollution in the city caused by the Big Dig. In 2005, the Conservation Law Foundation (CLF) sued the state because it had not taken the necessary steps to complete the project on time. In November 2006, CLF and the state settled and agreed on a binding commitment to complete the project by 2011. That commitment was pushed back to 2014.

That three year delay from 2011 to 2014 is what may give the city leverage in trying to get a commuter rail stop from the state, said Alderman-at-Large William A. White.

“Somerville has suffered from the loss of the Green Line and will continue to suffer for those three years. We have a bargaining point there we may be able to use,” he said. “My understanding is adding a temporary stop would not be a major expense for the state.”

Ward 6 Alderman Rebekah Gewirtz enthusiastically supported O’Donovan’s proposal.

“This is a great idea,” she said. “We have a tremendous amount of rail lines running through this city yet only one stop in Davis Square.”