IPSWICH — Selectmen are filing notice of the town's intention to make safety improvements at the Topsfield Road crossing commuter rail line. The notice, approved unanimously last night, also asks that all the town's crossings be considered one quiet zone, where train whistles are not sounded.

Their other option was to ask that the crossings at Washington, Mineral and Liberty streets and Linebrook Road be declared an established quiet zone, with Topsfield Road being considered separately.

Either action would comply with the requirements of the Federal Railroad Administration's new train whistle rules. In June 2005, the federal agency issued its final ruling on when and where trains have to blow their whistles when approaching crossings. Essentially, whistles must be sounded at every crossing in the country unless local officials could document a historical ban on them, or they took additional steps to make their crossings much safer than they were.

In Ipswich, there was a problem at Topsfield Road. Two accidents had occurred at the crossing in the previous five years. One of those subsequently got taken out of the formula used to calculate safety at the crossing, but the other won't come off the books until March 2009.

To make the crossing safer, the town must now present plans for improvements that would achieve that end, and the cost could be in the millions of dollars.

The accident that has caused all this trouble occurred when a woman stopped her car when she thought she was outside the crossing's gates, though she was still inside. Her car was struck by a train, but the selectmen don't think the accident should affect the crossing's safety rating. To that end, they intend to ask the FRA to grant a waiver and take the accident out of the equation.

They broached the subject during a visit with Randy Dickinson, program manager for rail crossings in the Federal Railroad Administration's local office, several weeks ago.

Dickinson told them there's no chance they'll get a waiver, but selectmen said they believe there's little to lose.

In a memo to selectmen, the consultant who has been advising the town on the whistle ban recommended working with the MBTA to draft the waiver request.

Whether the T will take part in that exercise is a good question, since the agency has demonstrated it's at least as averse to whistle bans as the FRA, if not more so.

And an accident is an accident, and if the FRA's recent actions in Little Falls, Minn., are any indication, every quiet zone is always at risk of losing its status.

Little Falls established itself as a quiet zone in 2006, but since then an increase in traffic at one crossing and a collision between a train and a pedestrian there have dramatically increased the town's "risk index." According to federal documents, the FRA is reviewing whether the "quiet zone designation should be terminated or whether additional safety measures may be necessary to ensure motorist safety."