The trailer being towed by the tractor overturned on the A442 at the Leegomery roundabout in northern Telford.
The crash on the Queensway happened just before 5pm, with a street lamp damaged.
AA Roadwatch said traffic was queuing in both directions, with queues backing up to the Hadley Park roundabout to the east and even further down the A442 to Trench Lock.
Police were on the scene amid heavy rain.
It is not yet known if the driver or anyone else was injured.
The A442 at Leegomery, Hadley Castle and Trench Lock forms part of a 29-mile diversion route for motorists while a section of the A41 north of Newport is shut for roadworks.
The A41 is expected to be shut until early September, and earlier this week drivers attempting to avoid the lengthy diversion filled up country lanes in villages and hamlets north of Telford.