Currently members of the Massachusetts State Police are on the scene of a Tractor Trailer Rollover on RT 495 NB in Marlborough at the bottom of the ramp from RT 290 EB.? Troopers from the State Police Barracks in Leominster, the Barracks in Holden and the Troop C Community Action Team (C.A.T.) along with Troopers from the MPS Commercial Motor Vehicle Enforcement Section and the Marlboro EMS. ??The operator of the TT Unit is the lone occupant of the vehicle.? The status of the operator is unknown at this time.? ?All lanes of travel on RT 495 NB are closed to traffic at this time.? The Mass Department of Transportation (Mass DOT) is responding with arrow boards to help re-route traffic.? Traffic delays are expected.? This is a developing situation and more information will be released as it becomes available.?