In its heyday it was a key part of the North East railway lines.

Today, it is a haven for walkers, photographers and explorers alike.

Tunnel sits at the back of Lebrina, just a few kilometres past Lilydale, in the state's North East.

It is relatively hidden, and its location passed on mostly through word of mouth.

Work on building the structure's approaches began in late 1885, Stuart Dix said.

Mr Dix is the secretary of the Tasmanian division of the Australian Railway Historical Society.

It would be a further two years, Mr Dix said, until the two headings met.

It was another 12 months until the 700-odd metre tunnel reached completion.

The first passenger train to run through the tunnel took its maiden voyage on February 2, 1889, with special cargo aboard in the form of the Governor.