Santa Clara County Supervisor Liz Kniss and Assemblywoman Sally Lieber intervened on behalf of residents and encouraged Union Pacific Railroad to halt its night trains.

Since spring, noise from Union Pacific freight cars en route to Cupertino's Hanson Permanente quarry frequently awakened residents living close to the railroad tracks. At times, trains hauling coal and raw materials ran after midnight. In Saratoga, residents have also complained of nighttime horn blasts at railroad crossings.

This should change.

"Sally Lieber spoke with Union Pacific officials and got a commitment from them to go back to daylight hours," Monica Smith, Lieber's district director, said.

"It's supposed to have happened starting Aug. 15," she said, "but it depends on finding four-axle locomotives."

The problem began when Union Pacific switched from running freight trains during the day to nights to accommodate construction of a Silicon Valley Transportation light rail project. After VTA completed the project, Union Pacific continued its night runs from San Jose to Cupertino, partly because of the limited availability of the four-axle locomotives.

The resulting noise from the night trains left some residents feeling as if they were going off the rails.

Cupertino officials were unable to help since the federal government regulates the railroads. However, Lieber and Kniss decided to deal directly with the railroad company.

Kniss wrote a letter to Union Pacific, with copies to nine public officials, including Sens. Dianne Feinstein and Barbara Boxer, urging them to correct the situation.

Residents say it's already quieter at night.

"In the last four to five days Union Pacific has been bringing in shipments during the afternoon," John Giovanola, Hanson's community affairs officer, said. "We're going to make an attempt to make sure that continues."

"This is a good sign of progress and getting back to daylight hours," Union Pacific official Mark Davis said.

"We're very thankful," Giovanola said. "[Union Pacific officials] have said it doesn't guarantee there will be no trains running at night, but they are trying their best to bring them in during the day."