CHICAGO — US Senator Dick Durbin told Norfolk Southern this week that it must do more to secure a major rail yard on Chicago’s South Side after three major gun thefts led to many of the weapons circulating in nearby violence-plagued neighborhoods, according to a letter the Illinois Democrat sent this week to the company’s CEO.

The letter, provided by Durbin’s office Wednesday, cites the theft of some 150 guns between 2014 and 2016. Officials say most of the guns, including semi-automatic rifles, spread into nearby communities, helping to fuel the kind of violence that last year led to 762 homicides in Chicago, more than in New York City and Los Angeles combined.

‘‘These repeated incidents of gun theft . . . jeopardize the safety and well-being of Chicago residents,’’ Durbin wrote in the March 14 letter to CEO James A. Squires.

There have been no federal or local hearings on the rail-yard gun thefts, contributing to a perception in neighborhoods near the yard that no one is taking responsibility.

The railway did not reply to a request for comment.

Associated Press