Two-person train crews aren’t necessary for rail safety, the Federal Railroad Administration said in withdrawing a proposed rule that would have regulated staffing.

Regulating train crew staffing isn’t “necessary or appropriate for railroad operations to be conducted safely at this time,” the agency said in withdrawing a March 2016 proposed rule issued after a pair of 2013 rail accidents in the U.S. and Canada, including one in Quebec that killed 47 people.

The withdrawal will be effective upon the FRA notice’s May 29 publication in the Federal Register.

The withdrawal is intended “to preempt all state laws attempting to regulate train crew staffing in any manner,” the FRA said. California, West Virginia, and Wisconsin require a minimum of two crew members for certain trains, while Arizona, California, Ohio, and Oregon have “full crew” requirements for certain trains, and Massachusetts, New Jersey, and Washington impose other restrictions, the agency said. Colorado and Nevada have recently enacted laws requiring two-person crews for some trains.