The tunnel is straight, and was originally single-lane and gravel-surfaced. The tunnel walls remain unlined granite. The east portal end is at 945 m elevation; the tunnel runs 1270 m at approximately a 1:10 gradient down to the western portal. Until it was sealed and enlarged it was the longest gravel-surfaced tunnel in the world. It runs between the valley of the Eglinton and Hollyford Rivers to the east and that of the Cleddau to the west.
William H. Homer and George Barber discovered the Homer Saddle on January 27 1889. Homer suggested that a tunnel through the saddle would provide access to the Milford area.
Government workers began the tunnel in 1935. Progress was slow, with difficult conditions including fractures in the rock bringing snow flows into the tunnel. Compressors and a powerhouse in the nearby river were built to pump out 40,000 litres of water per hour. Work was also interrupted by World War II. These problems delayed the tunnel's completion until 1953. The Homer Tunnel was opened to private traffic in 1954.
In 2002 a tour bus carrying tourists from Singapore caught fire inside the tunnel, halting 150m from the eastern portal. The passengers, including the bus driver, had to tread through the pitched dark and smoke-filled tunnel to safety with the help of head beams from vehicular traffic at the entrance of the eastern portal. However, two passengers got separated and made their way to the Milford end. Three people were treated for smoke inhalation.
Traffic through the tunnel reaches about 800 vehicles a day in summer, with about 100 tour buses.
Roof lighting was fitted and traffic lights reintroduced in 2004. Although the tunnel is large enough for a bus and a smaller vehicle to pass, cautious campervan drivers often cause problems. Fortunately the heavy traffic is mostly toward Milford in the morning and toward Te Anau in the afternoon. The traffic lights will only operate during the peak summer season, since the avalanche risk makes it unsafe to stop and queue at the portals in winter and spring.
 External links
- Homer Tunnel info in the 'Encyclopedia of New Zealand 1966'
This article uses material from Wikipedia, "Homer Tunnel"