Lt. Gov. Timothy P. Murray said yesterday that railroad company CSX Corp. is blocking the expansion of commuter rail service to the city, and he reproached CSX for neglecting the public interest.

At a railroad summit at the DCU Center, Mr. Murray used harsh terms to describe the current stalemate between CSX and the state. The policies CSX is proposing, he said, are "absurd."

"Despite CSX's apparent indifference to the public interest, we are not dissuaded in our effort to expand rail to Worcester and other parts of the state," he told a packed conference room, including CSX representatives sitting in the front row.

The expansion of commuter rail service to Worcester has been discussed for years, but has not moved beyond talks, largely because of a dispute over liability. CSX, which owns the track from Framingham to Worcester, insists on maintaining the existing no-fault liability policy if the state purchases the track.

The 22.8-mile section from Framingham to Worcester is one of the few pieces of railroad used by passenger trains that is not owned and controlled by the state. Mr. Murray and other politicians say acquiring the right-of-way on that track is the best way to expand commuter service and spur economic growth, but if the state buys the track, liability should be determined by who is at fault in an accident. Otherwise, politicians say, taxpayers could end up footing the bill for CSX's negligence.

"No-fault is a deal breaker," Mr. Murray, the former Worcester mayor, said yesterday.

He has voiced that point before, but not in such blunt terms at a well-attended public event.