The former police chief in Elmwood Park, N.J., vividly remembers the moment 30 years ago when the gates at the railroad crossing on the edge of town lowered on the bus carrying his son and his classmates on a field trip.

Suddenly, they were trapped on the tracks, with a train bearing down.

“The fathers got out and started trying to push the rails off the bus so it could move,” the former chief, Don Ingrasselino, recalled. “We were all shouting at the bus driver to move, move. She was finally able to get out of there, but I still think about how many kids could have died that day.”

Through the decades, Mr. Ingrasselino would respond as a police officer and chief to a number of tragedies at the crossing, where Midland Avenue intersects with New Jersey Transit tracks at a sharp angle through his Bergen County town.

“It’s not even an accident waiting to happen,” said Mr. Ingrasselino, who retired in 2012. “It’s an accident that’s been happening, over and over. It’s ridiculous.”