According to the Roosevelt Island Operating Corp (RIOC)

Please be advised on Sunday, November 11, 2012 between the hours of 6:00 AM and 2:00 PM, the Roosevelt Island Tramway will be conducting a mandatory rescue and evacuation drill.

The Tram will operate only one cabin during this important exercise.

Sincerely,

Roosevelt Island Operating Corp Advisories Group

Here’s previous NYPD Tram Rescue Drill, FDNY rescue drill and with the NYPD K9 Dog unit.