A collection of walks, discoveries, insights and pictures of exploring Dartmoor National Park
August 19, 2020
CANTRELL (processing plant) TO REDLAKE (clay extraction) – A JOURNEY FOLLOWING THE TRAMWAY & PIPELINE
This post relates to the Tramway and Clay pipeline which extend from Cantrell, just outside Ivybridge, through to these two the Red Lake and Left Lake clay extraction locations.
The tramway was first surveyed in 1909 by R. Hansford-Worth to ascertain the feasibility of connecting Red Lake to transport links and hence the outside world. There had been around 4 years opposition to the venture as one might imagine including legal action. The protests included a Dartmoor Preservation Association protest in 1910. The construction of the tramway started in the latter half of 1910 with a gang of around 30 men. Initially, a temporary 2ft gauge track was laid, whilst the track bed itself was prepared. The final gauge of the line was 3ft. The sleepers were made of English oak and the rails were “fixed down” with bolts, clips and dog spikes. Ballast was provided by means of a quarry below Western Beacon, with a supplementary stone crusher at Three Barrows. For the record, 550 tonnes of rail were used alongside 16,000 oak sleepers.
The tramway construction was rapid, thanks to the course selected and it was officially opened on 11th September 1911 (albeit not 100% of the track had at that time been laid). It was finally completed in November 1911.
The Greenhill Micas complex was the initial clay processing section about a mile or so south of Red Lake. Greenhill is higher than the clay operation at Redlake and the author believes that this “hill” would have presented both a problem and ultimately the solution to the clay men in their desire to create a “gravity” fed pipeline to Cantrell some 8 miles away. Although not documented as such, it is theorised that the hill was chosen as the pre-processing complex rather than a location closer to Redlake. It not only provides natural contours for the process (ie dispensing filtered clay from one process to the next) but also the obvious place to start their “gravity” fed pipeline as from this point it is all downhill to Cantrell. The clay would have had the consistency of cream and was fed into a twin stoneware pipe system, relying solely on the 1000 ft height drop to Cantrell.
The pipeline today can be followed all the way from Greenhill Micas to the top of the incline plane above Cantrell. Along its route would have been 80 inspection points (only 76 are extant today with numbers 77-80 being cleared beside the incline plane). The pipeline was for much of its length buried just below the surface but three concrete bridges and some platforms were required at various points along its route due to the nature of the terrain. When the pipeline was first completed around late 1913, it was discovered that for approx. one third its length, it had water ingress and thus joints had to be dug up and had to be re-worked. This caused months of delay and ultimately Handsford-Worth his job (as he had supervised the pipeline contract).
The stoneware pipeline was washed out with water for 15 minutes before clay was fed into it. Apparently, the clay sometimes froze and was unable to be washed out. At Leftlake, the pipeline disappears underground near the brick-built bridge and the author suspects that it is an integral part of that construction. At Leftlake (from 1922), the clay from that operation entered the pipeline. The two sources of clay were never mixed as that at Leftlake was considered inferior quality. The point where the Leftlake clay was added appear to be at the 22nd Inspection point from Greenhill. It is unfortunate that the pipeline is on the opposite side to the tramway from the Leftlake micas, so one assumes a temporary pipe laid across the track when the clay feed was being used.