All public buses now enter the central area through the main tunnel.
Forty minutes went by before the main tunnel came into sight.
It seemed that what we had dug into wasn't the main tunnel after all.
Bond drew the girl a few feet up the main tunnel.
He was still hundreds of meters from the main tunnel.
She led him up the main tunnel for a long way.
From the river to the ceiling of the main tunnel must be thirty feet or so, he thought.
On days when his job was near the main tunnel, he sometimes walked along the river after he'd finished working.
She was on her feet and running back toward the main tunnel.
She could see partly into the little room at the end of the main tunnel.
