Senator Chuck Schumer implored the federal government to start testing train operators for sleep apnea in a letter Sunday, after engineers in a series of crashes were found to be suffering from the disease.

Schumer expressed “serious concerns” about the Department of Transportation’s August 2017 decision to withdraw a proposed rule mandating the testing and screening of train engineers for sleep apnea, in a letter to Transportation Secretary Elaine Chao obtained by the Post Sunday.

“I urge you to immediately reconsider your decision to withdraw the proposed rule in order to help avoid future fatigue-related tragedies,” the senator wrote.

Schumer quoted National Transportation Safety Board Chairman Robert Sumwalt who said he was “mystified” by the withdrawal at a Feb. 6 meeting.

The NTSB linked the disease to a number of recent rail accidents, including a deadly Sept. NJ Transit crash and a Jan. 2017 Long Island Rail Road accident and found that regular testing could have prevented the incidents.

“The proposed rule consisted of a modest, common-sense approach to combating fatigue on our rails and roads: require testing for obstructive sleep apnea if a problematic symptom is observed,” the senator wrote.