Amtrak officials, examining the neighborhood shortcut where a Lanham mother was killed Monday while protecting her son from an oncoming train, said yesterday they will seek funds to erect fences and signs to prevent people from crossing railroad tracks.

Pedestrian deaths along the northeast rail corridor have become such a problem that the rail system set up a task force four months ago to seek solutions, said Lee Williams, safety manager of Amtrak. Its report is due April l.

But Williams could not say whether the well-worn path across the tracks between the Whitfield Towne Apartments and nearby stores on Rte. 450 would be fenced.

A fence, Williams said, might not have prevented the death of 36-year-old Mary E. Stevenson. "You put a fence up and the kids quickly tear it down."

Authorities said Stevenson was returning from shopping at the Safeway on Rte. 450, carrying groceries, with her 3-year-old son, Tavares, trailing behind her. They had crossed three pairs of tracks when the boy fell between the last pair of rails. According to Williams, Mrs. Stevenson saw the Philadelphia-bound Chesapeake train rounding a tree-shrouded curve about 200 yards away and threw herself over her son.

The train, despite the application of brakes, ran over her. Her son remains in critical condition at Johns Hopkins Hospital's pediatric intensive care unit with massive injuries, including a severe skull fracture. Doctors were unable to save the boy's right hand, which was severed just above the wrist, according to a hospital spokeswoman.

"People just have to realize that these trains cannot stop on a dime," Williams said.

According to residents, the children and adults at the Whitfield Towne Apartments make at least a hundred trips a day across the tracks instead of taking the 10-minute walk over the bridge at Rte. 450. Five residents interviewed said that the tracks usually "sizzle" with the approach of a train, but the quiet electric motors provide little additional warning. The trains' horns usually sound once as they round the curve.

"And if you missed that horn once, that's it," said Michael Hill, 23, a resident who often crosses the tracks.

Lynn Nagel, an area resident, said, "I tell my daughter constantly, 'Don't cross the tracks,' but that won't stop her from doing it." Other residents agreed that the traffic across the tracks, which includes children with bicycles, will resume.