It started by taking over an obsolescent horse-operated tramway in 1862, and it improved and extended it, connecting Newquay and Par Harbours, and Fowey.

Kaolinite, generally known in the United Kingdom as china clay, was extracted in the Hensbarrow area north-west of Luxulyan and the mineral was also brought to Pontsmill.

Treffry soon expanded his interests by building a horse-operated tramway up the Luxulyan Valley to Molinnis, near the present-day Bugle; this line opened in 1844.

Treffry had made it clear that he wanted to connect these lines, forming a through route between Par and Newquay; in particular this would have enabled copper and tin ores to be exported from the north coast of Cornwall to South Wales, and coal to be imported that way, avoiding the difficult shipping route round Land's End.

As part of the agreement, Roebuck undertook that if he was successful in acquiring the N&CJR line he would lay broad gauge rails on the former Treffry line from the point where the two lines met as far as Newquay, and improve the route for locomotive-operated passenger trains from Burngullow to Newquay; and similarly if he acquired the Lostwithiel and Fowey Railway he would extend that to Fowey Harbour, as its southern extremity was at deep water jetties at Carne Point, some distance north of Fowey itself.

c. clxii) to acquire and improve the Treffry Tramways, and to build new railways to connect St Dennis (then called 'Bodmin Road Junction') and Molinnis; and to acquire the Newquay and Cornwall Junction Railway and to build a line between its northern end at Nanpean (Drinnick Mill) and Hendra.

Moreover, a new line connecting St Blazey (near Par) and Fowey Harbour was to be built, with jetties and wharves there, and improvements to the quays at Newquay.

This was a massive project; the improvements to Treffry's line involved a new alignment 21⁄2 m (4 km) long in the Luxulyan Valley, which was difficult terrain for railways: the Carmears incline was to be by-passed.

[10] The Treamble branch was extended to Gravel Hill where there were iron ore deposits; this was an addition to the originally authorised network, and was done by arrangement with the landowner and without parliamentary authority.

c. clxii) had required the CMR to lay the Drinnick Mill to St Dennis section in mixed gauge, giving the Cornwall Railway broad gauge access to St Dennis; this obligation had been incorporated into the Newquay and Cornwall Junction Railway Act 1864 (27 & 28 Vict.

In fact the Cornwall Railway petitioned in the Court of Chancery for the broad gauge rails to be added, and this was done in the following year (June 1875), although they were arranged so as to be unusable.

[7][11] Mineral extraction in Cornwall was always susceptible to world price fluctuations and at the time of opening of the CMR lines, cheap iron ore production in Spain and elsewhere developed and made the Cornish mines uneconomic; numerous iron ore mines closed suddenly.

In addition china clay production was significantly reduced by agreement between the pit owners, following price depression due to over-production.

These factors led to a desperate situation for the CMR which had made considerable financial outlays and was now unable to obtain income, and some major shareholders were severely embarrassed.

[8] Seeing the income from mineral traffic so deficient, the company started a passenger service between Fowey and Newquay, using six second-hand coaches probably obtained from the Midland Railway.

In the following years, the very depressed state of mineral trade in Cornwall revived somewhat, and with it the traffic on the CMR network, and the lease charge received from the GWR.

On 2 October 1893 a more ambitious new line from Goonbarrow Junction (then referred to as Roskear Sidings) to Carbean; this section was 3+1⁄2 miles (5.6 km) in length.

A shorter branch, half a mile (about 1 km) in length was opened on the same day from Bugle to Martins Goonbarrow and Great Beam.

The CMR became interested in it as its jetties were usable, and it purchased the line from the insolvent owners; the transfer was authorised by the Lostwithiel and Fowey Railway Act 1892 (55 & 56 Vict.

This became known as the Wheelpit Mill and the resulting material was piped down to Pontsmill in slurry form in a pipeline laid on the course of the former tramway incline.

[2][page needed] The Cornwall Minerals Railway network was leased to the GWR, and was being operated by that company, and discussions started regarding a transfer of ownership.

A short branch extension was built and the stub of the old line renovated to serve the location; a petrol locomotive was used to trip from Pontsmill itself.

Notwithstanding the objections of the GWR, the mining company's rights prevailed, and the line was severed, creating the so-called Carpella Gap.

[2][page needed] In connection with the building of the Truro line, the opportunity was taken to substantially enlarge and modernise the Newquay station, to accommodate the additional traffic.

The formation was widened to make a two lane road, and ECC undertook a major modernisation of the handling equipment at Fowey.

The railway route is almost entirely preserved as part of the haul road, including Pinnock Tunnel; it is now owned by Imerys.

[16] Freight is handled between St Dennis Junction and Par, and the Lostwithiel to Carne Point line is also in use for mineral traffic.

[18][page needed] The Cornwall Minerals Railway built St Blazey workshops to house and maintain its 18 locomotives.

After two fairly level miles comes a long climb up the Luxulyan Valley, some of it at 1 in 37, followed by slightly easier gradients to the summit at Roche, after which there is an almost continuous fall to Newquay.

The line between Fowey and St Blazey was closed in October 1968, and the trackbed was converted for use by English China Clays International as a road haul route; Pinnock tunnel is operated on an alternating one-way basis, controlled by traffic lights.