According to the MTA:
Details about service changes in effect along E, F, M and G lines. pic.twitter.com/LbBzTD57JANYCT Subway (@NYCTSubway) July 17, 2017
The service disruptions were caused by smoke in the 63rd street tunnel according to FDNY personnel
at the Roosevelt Island F train station.
According to the Roosevelt Island Operating Corp (RIOC):
MTA has advised that due to a smoke condition there is NO “F” train service in either direction. Please plan your travel accordingly and visit mta.info or call 511 for more information.
For electronic updates on F Train service, sign up for MTA Alerts at mymtaalerts.com
and :
Following a previous disruption, the MTA has advised that F Train service has resumed. Expect residual delays and plan your travel accordingly, visit mta.info or call 511 for more information.
For electronic updates on F Train service, sign up for MTA Alerts at mymtaalerts.com.
Service resumed with delays at about 4:30 PM.
Following earlier FDNY activity at Lexington Av-63 St, E, F, G and M train service has resumed.NYCT Subway (@NYCTSubway) July 17, 2017
