Work is starting on a footbridge to link a new secondary school in the Isle of Man with an estate.
The 22-metre bridge is seen as a key milestone in the construction of the £33.8m St Ninian's Lower School, at Bemahague, Onchan.
The bridge will connect the school with the Governor's Hill estate.
The new school, due to open next September, will accommodate 700 students from years seven to nine.
The Mountain Road was closed between Signpost Corner and Governor's Bridge from 06:00 BST.
It is scheduled to reopen no later than 17:00 BST on Friday.
Richard Collister, estates director with the Department of Education and Children, said the bridge would provide safe access over the busy TT course at Hailwood Avenue corner.
Mr Collister said: "Subject to any delays caused by the current unsettled weather, we will have the bridge installed by Friday evening.
"We appreciate the closure of this major road will inconvenience motorists and we thank them for their patience while this vital part of the Bemahague school project is completed."
It is hoped that the bridge will be in use by the public by late-November.