Tavistock Canal - Archaeological Excavations

Canal Incline - 2009-10 Excavation

A sample length of the double-tracked Canal Incline, constructed in 1815-16, was excavated over the winter of 2009-2010. This followed on from a previous metal detector survey of this and a lower section, which showed that a significant quantity of scrap metal relating to the incline's construction and use had survived, on and around its formation.

The excavation was designed to record the form of the two lines, one of which could be seen to be set at a slightly lower level than the other. This was shown to be due to the reconstruction of the western line c.1855 as an edge railway, with new sleeper blocks and trackwork, at a slightly higher level than the eastern line, which remained a plateway to the incline's closure in 1873.

The excavation plan shows the granite plateway sleeperblocks and killas (slate) chain-rubbing slabs in red and the killas sleeperblocks for the 1855 railway in green. Some of both, but especially the killas blocks, had been removed, possibly for agricultural walling, after abandonment; the various pits in the trackbed showing where these were once sited.

The area of the plateway incline between the rails had two inwardly-sloping bands of pitched killas cobbling, flanking a slabbed central rubbing-strip for the haulage chain to run in. At intervals, plank boxes containing cast iron rollers ensured that the slack chain ran evenly and in-line on the incline. Despite this, the rubbing-strip was heavily scored by the chain. Remains of only one plank box was found in the 20m long stretch of incline sampled, so the distance these were set apart is not known. Plank boxes for rollers are known from another Taylor incline, that at Goginan Lead Mine in Flintshire, North Wales.

The c.1855 edge rail incline also had rubbing stones, some of which had clear scoring from a wire rope, known to have been used for haulage there. These stones were set at intervals, with ash ballast between, which would have caused rapid wear of the rope. It is not known whether rollers were used on this reconstructed line.

See also: Canal Incline - 2009-10 Excavation - Gazetteer...