NEWARK, N.J. (CBSNewYork/AP) — Twelve NJ TRANSIT train operators have now been pulled from service after they showed signs of sleep apnea, the transit agency said Thursday.

The removals, which NJ TRANSIT confirmed to CBS2, follow new rule in which NJ TRANSIT is no longer allowing its engineers who exhibit symptoms of sleep apnea to operate trains pending diagnosis and treatment.

NJ TRANSIT Executive Director Steve Santoro said that under the program begun in October, engineers and conductors who show indications of potential fatigue symptoms will be removed until they can document they’ve controlled or corrected their conditions.

The new rule was the result of a new staff position taking a look at the physical exam process.

It was also part of the proactive measures following the deadly Hoboken train crash in September, in which the engineer was later found to have sleep apnea, NJ TRANSIT said.

NJ TRANSIT engineer Thomas Gallagher was diagnosed with the sleep disorder just a month after the accident, CBS2 reports.

The Federal Railroad Administration last month announced plans for a safety advisory asking railroad systems nationwide to test train operators for sleep disorders.

The advisory, akin to a strong recommendation, is a stopgap measure while regulators draft rules that would require railroads to screen engineers for sleep apnea. That process could take years, and FRA Administrator Sarah Feinberg said railroads shouldn’t wait for the government to force action.

Sleep apnea is especially troubling for the transportation industry because sufferers are repeatedly awakened and robbed of rest as their airway closes and their breathing stops, leading to dangerous daytime drowsiness.

Airplane pilots with sleep apnea aren’t allowed to fly unless they’ve been successfully treated. Regulators are also pushing for bus and truck drivers to get tested.

One person was killed and more than 100 were injured in the train crash on Sept. 29.

Gallagher, 48, told investigators he had no memory of the crash and remembered waking up on the floor.

NJ TRANSIT has said it has a sleep apnea screening program, but said it could not discuss any specific employee’s medical or personal information. It was not immediately clear if Gallagher was screened.

In December 2013, a Metro-North Railroad engineer William Rockefeller, also had undiagnosed sleep apnea, fell asleep at the controls for his train and failed to slow down for a sharp curve. Four people were killed and more than 70 were injured when the train derailed in the Spuyten Duyvil section of the Bronx.

Metro-North started testing for sleep apnea after the 2013 crash. Metro-North’s screening program has found sleep apnea in 51 of its 438 engineers and trainees, spokesman Aaron Donovan said. They are undergoing treatment, he said.

Metro-North has found that one out of every nine of their engineers suffers from sleep apnea.

The Long Island Rail Road is in the process of starting a testing program.

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