Nerissa Dexter says that when she presented the results of her research showing Atherton could impose a quiet zone around its Fair Oaks Lane railroad crossing, where train horns can sound only in an emergency, many people believed it was just too good to be true.

"The biggest problem I encountered initially is nobody believed it," she said. "It was too simple."

Atherton's quiet zone, an area a quarter-mile on each side of the Fair Oaks crossing, went into effect on Monday, June 13. The quiet zone is the first in the Caltrain corridor, and many other cities are looking to see what happens in Atherton before they try to do the same.

Residents and town employees say the quiet zone has made a huge difference in the amount of train noise.

But when, a few days after the quiet zone had gone into effect, town officials pointed out to Caltrain that some train horns were still sounding in the quiet zone, the response was not what the town wanted to hear. Loopholes in the law, Caltrain said, mean its train operators are still allowed to sound their horns in much of the quiet zone.

Is the quiet zone law actually too good to be true?

Maybe not.

The dispute

Caltrain spokeswoman Tasha Bartholomew said on June 17 that despite the quiet zone, "Caltrain engineers can still sound the horn through the Atherton station." The station is next to the crossing inside the quiet zone.

The reason, Ms. Bartholomew said, is that "the Atherton train station includes five pedestrian crossings that require all Caltrain trains to sound horns as they transition the station."

Caltrain also has an "operating rule" that requires train horns to sound while passing through train stations, she said.

The town begs to differ.

While Federal Railroad Administration regulations do say that if state laws require a train horn to sound at pedestrian crossings, then they may do so even in a quiet zone, the town says it doesn't actually have any pedestrian crossings.

A letter from City Manager George Rodericks sent to Caltrain in May said that what Caltrain, and the state Public Utility Commission, calls pedestrian crossings in the Atherton station are not actually pedestrian crossings. The station does have spots in which pedestrians cross the southbound tracks in order to board a northbound train, but pedestrians are only to cross once the northbound train is stopped in the station. Trains currently stop at the Atherton station only on weekends.

Signs say: "Please wait behind the yellow line" on the southbound side of the tracks and "Danger, not a waiting area," between the two sets of tracks.

The boarding platform is "not an independent pedestrian crossing of the tracks," Ms. Dexter said.

"Until we are shown, in writing how Caltrain policy ... contradicts and overrides our understanding of the applicable FRA (Federal Railroad Administration) regulations we stand by our assessment that they may use locomotive bells within the station but not sound the horn" unless there is an emergency, City Manager George Rodericks said on June 17.

If Caltrain proves correct, however, it reduces the area governed by the quiet zone down to only the quarter-mile north of the Fair Oaks crossing.

Genesis of quiet zone

For years, perhaps decades, Atherton has been trying to convince Caltrain to stop, or at least limit, the sounding of train horns as trains pass within yards of many Atherton back-yard fences, its park and its town offices, library and council chambers.

But the town has long been told that it just doesn't meet the safety requirements for a quiet zone.

Last year, however, when members of the town's Rail Committee, heard yet another report that the town wasn't eligible for a quiet zone, Ms. Dexter said something just didn't seem right to her. The report said Atherton was not eligible because of "nearby fatalities," but, Ms. Dexter said, there had been no fatal accidents in the town's crossings.

So she went online and starting researching the federal regulations on quiet zones. She spent hundreds of hours on the projects, talking to officials in other communities with quiet zones, getting answers to technical questions from experts in the field, as well as reading not only the laws governing quiet zones, but the legislation that led to their creation.

Counting Atherton's quiet zone, there are now 47 California quiet zones, including most of Orange County and most of San Diego.

What Ms. Dexter found, she reported, first to the Rail Committee and later to the City Council, was that the quiet zone regulations are meant to make rail crossings safer. "Train horns are not meant to be a gold standard of safety," she said. Train horns can warn people and vehicles that a train is coming, but they do not keep them off the tracks, she said.

Certain safety measures, including what are called "quad gates," which lower four arms at a crossing so even the most determined driver can not get around them, provide more safety than train horns, Ms. Dexter said.

Other required safety measures are already in California crossings. Devices called constant warning time circuitry sense not only when a train is coming, but its speed and distance, and automatically lower the crossing gates and set off warning bells 40 seconds in advance.

Crossings also have sensors that keep vehicles from being trapped inside the gates by keeping the crossing gates open if a vehicle is on the tracks.

The regulations are written to allow a community with the specified safety measures to declare a quiet zone that only the Federal Railroad Administration can deny. It can be as small as one crossing.

Atherton hired a consultant, R.L. Banks & Associates, to confirm Ms. Dexter's research. Soon after, the town went ahead with the paperwork needed to declare the quiet zone around one of its two railroad crossings.

Atherton's second crossing, at Watkins Avenue, needs further safety measures before it qualifies, and the town is currently studying installing those measures.

Local reaction

While the town and Caltrain squabble over just how quiet the quiet zone must be, local residents say they have already noticed a huge difference.

Bob Shypulski, who has lived in Atherton's Lloyden Park neighborhood since 1992 and owns the Shypulski and Associates hair salon on Chestnut Street in Menlo Park, said the difference since the quiet zone went into effect on June 13 is "just incredible. I didn't realize how loud the horn was," he said.

"If we don't need to hear the horn all the time, it's great," he said.

Many of his clients who live in Atherton feel the same way, he said. "Everyone's thrilled. They can't believe it actually got accomplished and done. We're all happy as clams," he said.