It was a little over 5 miles (8 km) in length, running from Pontypridd to a junction near Caerphilly; from there to Newport existing allied railways conveyed the mineral trains.
In addition, the region at the upper part of the valleys was rich in mineral resources, in particular iron ore, coal and limestone.
The co-existence of these minerals encouraged the production of iron, but both that industry and the distribution of coal was limited by the very poor transport network, itself constrained by the valleys and intervening ridges.
[1][2] Throughout this period, mineral products were transferred from canal boats, and later from tramroad wagons, to ships for export of coastal transport at wharves on the River Usk at Newport.
[3] The volume of transported materials at Cardiff docks resulted in increasing congestion there, and it was reported that the masters of ships had to stand off for several days waiting for a berth to load their cargo.
[3] Lord Tredegar was involved in the discussion, and for him the enhanced traffic which would pass the Park Mile on his lands would bring in substantial extra toll charges.
Many of the directors and principal investors in the new company were involved in similar capacities with the Alexandra, and relations between the PC&NR and the A(N&SW)D&R were cordial.
[1] The line was duly constructed, but an intended opening at the beginning of 1884 was delayed: owing to a defect in one of the abutments of the bridge crossing the River Taff at Pontypridd, men are pulling it down and propping the girders with timber, so that many months must now elapse before the reconstruction will be completed.
[4]Even at the last minute there were problems which might have been foreseen: For some little time past, hopes and expectations have been entertained that the new Pontypridd, Caerphilly and Newport Railway would be opened for goods and mineral traffic today (Tuesday), but up to Monday evening [30 June 1884], the owners of the line, although they had made strenuous efforts with that object, had failed to remove all the difficulties which stood in the way, and in all probability the opening will not take place for several days to come.
[5]Those difficulties were resolved, but there was worse to come: Attempt to Open the Line: Obstructive Attitude of the Great Western Railway Company.
The train was moved to the limit of the boundary and left there, while most of the company proceeded to Newport to wait the result of a telegraphic dispatch to the head-office [of the GWR].
[6]The train stood immobile at Bassaleg for over a fortnight, until on 25 July 1884, the GWR and the PC&NR negotiated the necessary running arrangement.
Until that section was opened, the Pontypridd to Newport coal trains passed over the track of six railway companies in a journey of 19 miles (31 km).
A passenger service of three trains a day over the line was started on 28 December 1887; they ran from Pontypridd (TVR station) to Newport.
There were no stops on the PC&NR line itself; by this time the Gaer Loop at Newport was open, and the trains could run direct to the Great Western Railway's High Street station.
The through service from Newport was suspended from 1917 because of the pressures of World War I, and restored on 9 July 1923, and extended to Merthyr at that time.
[7] The Taff Vale Railway had been working the mineral trains between Pontypridd and Newport since the outset, but gave notice that at they wished to cease doing so in 1903.
[8] There had not been any intermediate stations on the PC&NR line, but in the first few years of the twentieth century, railway managers were considering how low-cost provision of passenger stops in lightly trafficked areas might be achieved.
The PC&NR decided to implement such a scheme, and acquired a railmotor, and a spare passenger coach was converted for use as a trailer.
From 1 May 1906 a new crossover adjacent to the stopping place meant that the returning train could immediately cross to the correct line.
It was a single line, and there was a difficult climb of 1 in 39 rising for loaded trains out of Caerphilly station, and these factors were a serious limitation on capacity.
It was decided to duplicate the worst part of the route on an easier gradient, and this was authorised by the Pontypridd, Caerphilly and Newport Railway Act 1887 (50 & 51 Vict.
[1] There was an obvious reliance by the PC&NR on the Alexandra (Newport & South Wales) Dock and Railway, and the latter was a much larger undertaking.