Johnson City is close to the complex, linked by a single tunnel.

The outpost commander tried to concentrate the men from the different tunnels and rooms into a single tunnel.

It was replaced by a single, larger tunnel in 1954.

This raised the safety standard to minimum requirements, but the traffic volume is still large for a single tunnel.

Currently the single tunnel has one lane of traffic in each direction.

The station is underground with 2 tracks in a single tunnel.

Later on, it was decided to alter this layout in favor of a single two-track tunnel under 60th Street.

The two areas are divided by a single tunnel that caters to pedestrians and the very few cars in the town.

In most cases both tracks are laid in a single tunnel.

The station is underground and built on a single tunnel with two tracks.