New York's Metropolitan Transit Authority downplays cell phone video that appears to show napping train conductor.
NBC News has obtained video showing a New York subway conductor slumped in his seat with his head down on an Uptown 1 train as it rumbled along late last week.
The Metropolitan Transit Authority says it is investigating.
The probe comes after WNBC aired a video from a viewer last week showing a train engineer reading a newspaper instead of looking at the tracks as he operated a morning rush hour Metro-North train to Grand Central Terminal.
Days after that report aired, another viewer contacted the station with concerns after seeing the 1 train conductor leaning over and resting his head.
That conductor was observed at about midnight last Friday.
Andrew Alpert, the chair of the New York City Transit Riders Council, an MTA oversight body, said the recent allegation was not as glaring or egregious as last week's incident because in that case, the engineer was actually driving the train.
The subway conductor in this latest video, Alpert said, is responsible mainly for opening and closing train doors.
"We don't know for how long he was nodding off, if in fact he was nodding off," said Alpert. "We don't know for how many stations that was -- was it just one station, and the guy just happened to capture it on his cell phone? We just don't enough. So when you don't know enough, you give the gentleman the benefit of the doubt."
The MTA said in a statement Wednesday that the video shows the conductor "did not appear to be alert, but it's unclear from this angle whether he was actually sleeping. We are investigating this incident and will take appropriate action."