Treffry owned the rich Fowey Consols Mine, which was worked by 6 steam engines and 17 waterwheels. Treffry linked his mine to his new port at Par by a canal. By 1847 J T Treffry had built a canal from Par to Ponts Mill. Treffry built the Par Canal by canalising 2.25 miles of the river and digging a new river channel slightly to the east. There was an entrance lock to the canal at the harbour, and then two more between there and its terminus at Ponts Mill, north of St Blazey.
He then built a tramroad from Ponts Mill (the canal head) to Molinnis near Bugle. Work began in 1835 with an inclined plane from the canal basin at Ponts Mill, past the Carmears Rocks, to the level of the top of the valley, then a level run through Luxulyan and on to its terminus at the Bugle Inn near Mollinis.
This required a high-level crossing of the river, for which they built the great Treffry Viaduct, 650 feet long and 100 feet high. It was built of stone from the Carbeans and Colcerrow quarries, and the lines from the quarries to the viaduct were the first parts of the railway to be operational. The railway was completed in 1844.
The viaduct carried both rails and a water channel to bring more water for the Fowey Consols. On its way down, the water was used to power the Carmears incline, by means of a waterwheel, 34 feet in diameter. This enabled the railway to work loads up the incline, against gravity.
This tramroad was extended alongside the canal down to Par in 1855, and replaced the canal. In turn the tramway was replaced by the Cornwall Minerals Railway in 1874, enabling the development of china-clay and china-stone works at the foot of the valley.
The tramway was then extended to a second port at Newquay. A connection from Par to the Cornwall Minerals Railway line to Newquay was opened on 1 January 1879. This was standard gauge and so traffic between this and the broad gauge Cornwall Railway had to be transferred between trains at Par until the broad gauge was converted in 1892 to standard gauge.
The Cornwall Railway was amalgamated into the Great Western Railway in 1889. The Great Western Railway was nationalised into British Railways in 1948, and this was privatised in the 1990s.
Par railway station is still open on the Cornish Main Line from Plymouth to Penzance. It is the site of the junction for the Atlantic Coast Line to Newquay.