The whole enterprise grew out of a closure. In 1972, flood damage shut the Glenreagh to Dorrigo branch line, a steep, scenic 69-kilometre railway that had climbed the range from the coastal lowlands up to the plateau. A year later, enthusiasts formed what became the Dorrigo Steam Railway and Museum with a simple, ambitious aim: restore the line and run it as a tourist railway through the mountains. While the track was repaired, rolling stock was gathered and stored, the beginnings of a collection that would grow far beyond a single branch line.

For a few years it almost worked. On 20 December 1984, the first section reopened, a locomotive hauling a train up from Glenreagh once more. On 5 April 1986 the line was opened all the way through to Dorrigo, two steam locomotives bringing 300 members over the final stretch to the terminus. The track still needed work, completed that October, but the dream of a working mountain railway had, for one season, become real. Then it stopped. A faction within the membership launched legal action over who owned the collection, the line slid back into disrepair, and the trains never ran in regular service. The dispute was not resolved until February 1999.

What the dispute froze in place was extraordinary. By 2017 the collection numbered some 75 locomotives, 19 railmotors and 280 carriages and wagons, the largest private railway collection in the southern hemisphere. It spans the whole story of New South Wales rail, government and private, from 1878 to 1985. Among the steam locomotives are two of the AD60 class Beyer-Garratts, articulated monsters weighing around 260 tonnes, the largest locomotives ever to run in the southern hemisphere. They sit now in long lines on the plateau, sleeping machines that once hauled the heaviest trains in the country.

There is something haunting about a collection this vast that the public cannot freely walk through. The diesels and electrics that replaced steam are here too, and the suburban carriages that once carried Sydney to work, all of it preserved at the quiet end of a dead-end line in cool, rain-soaked country. For decades the great hope has been the same: that one day the gates open, the rust is beaten back, and the largest railway collection in the southern hemisphere finally becomes a museum in full. Until then, Dorrigo holds, in trust and in silence, a complete century of Australian railways.