The Plymouth and Dartmoor Railway (P&DR) was a gauge railway built to improve the economy of moorland areas around Princetown in Devon, England. Independent carriers operated horse-drawn wagons and paid the company a toll. It opened in 1823, and a number of short branches were built in the next few years.
The Lee Moor Tramway (LMT) was opened as a branch of the original line in 1856; the extraction of china clay had become an important industry, and the LMT brought the mineral down to processing areas and to shipment at Plymouth. The LMT too operated with horse traction, in conjunction with steam locomotives and rope worked inclines.
The Omen Beam Tramway was an independent tramway for the gathering of peat from the moor above Dartmoor prison, for the manufacturing of naphtha.
The P&DR cost much more than the estimate and the intended generation of agriculture on the moor did not take place. The railway was dominated by a trading company who used it for bringing granite to Plymouth for coastal shipping transport. China clay deposits on Lee Moor were exploited and a branch of the P&DR was built to bring the mineral to Plymouth. The original P&DR line declined and its upper section was later adopted for the Princetown Railway branch line, but the LMT branch, and a short section of the lower end of the P&DR, remained in use until 1960. The line crossed the important Exeter to Plymouth main line on the flat, and many photographs have been circulated depicting the incongruous sight of the horse-drawn wagons crossing the busy main line railway.
Origins
Conception
Sir Thomas Tyrwhitt was a substantial and philanthropic landowner in Devon and Cornwall. He had founded the settlement that he called Princetown, on Dartmoor, and he was anxious to improve the living conditions of the inhabitants. Dartmoor prison had been completed at Princetown in 1809 as a prisoner-of-war detention facility, but the peace following 1815 emptied the prison.
Tyrwhitt wished to improve agriculture and extractive industries on Dartmoor, and he conceived the idea of a railway to connect Princetown and Plymouth. This was to bring lime and sea-sand up to the Moor for the improvement of land, together with timber and coal. Granite, peat, mineral products and agricultural produce would be carried down. Goods would be conveyed in wagons drawn by horses, on the turnpike principle, in which all-comers might run their wagons on the railway on payment of a toll.
He put forward proposals at Plymouth Chamber of Commerce in 1818 suggesting an 18% return on capital, and obtained subscribers, and a line was surveyed by William Shillabear of Walkhampton, a schoolmaster and surveyor. William Stuart was the engineer supervising the construction of the Plymouth Breakwater at the time, and this had a primitive internal tramway at the stoneyard. Stuart provided a cost estimate for the construction, and a parliamentary bill was submitted to form the Plymouth and Dartmoor Railway, with Stuart as its engineer. It was incorporated by the (59 Geo. 3. c. cxv) on 2 July 1819 with capital of £27,783, authorising it to build from Crabtree to Princetown.Carter refers to the company as the Plymouth and Dartmoor Tramroad, and Gillham refers to the Plymouth & Dartmoor Tramway (in Dart's book). The original company seal, illustrated in Kendall, names it the Plymouth and Dartmoor Iron Railroad.
Tyrwhitt ceremonially laid the first rail on 12 August 1819, but in fact contracts had not yet been let for the construction, and some re-appraisal of the engineering of the railway was to intervene. At a committee meeting on 26 July 1819 Stuart had been instructed to re-survey the line.
Extension to Sutton Pool, and first contracts
The line was to run from Crabtree to Princetown; Crabtree was chosen because it gave access to tidal water, at a small dock on the River Plym near the Rising Sun Inn there. The location was about east of the centre of Plymouth. However, the wharf would only be accessible at high tide and the river approach was lengthy and awkward, and it was decided to extend the course of the railway westward to reach Sutton Pool. Accordingly, a further act of Parliament, the (1 Geo. 4. c. liv), passed on 8 August 1820, was needed authorising the extension, and also a branch to the Cattewater. This added £7,200 to the projected cost of the line. The whole of this extension was referred to as the branch railway, being considered a branch from Crabtree. William Stuart was now appointed to superintend the construction. At this time the company had contemplated acting as dealers in granite, that is suppliers of the mineral at Plymouth, rather than simply carriers. There is reason to believe from committee minutes that they intended to do so, but the necessary clauses were not inserted into the 1820 act.
In April 1820, contracts had been let to William Bailey for the supply of cast iron rails; they were to be of the fishbelly pattern long and deep; they were to be butt jointed at the supports on stone blocks. The gauge was to be , it is not clear who chose this, or why.
A contract for the construction of the formation was let to Hugh McIntosh of London in June 1820, for 9s 3d per yard; it was to be a single line with a number of passing sidings (referred to as "turnouts")—two per mile. Some sidings – at least at Roborough and Yelverton – were to be constructed of granite blocks dressed so as to provide a flange guide, similar to the construction of the main line of the Haytor Granite Tramway.
On 21 September 1820 the committee signed a momentous agreement with the firm of Johnson and Bryse. They had acquired tenancy rights to extract granite from Dartmoor and needed to bring it down to Plymouth for use there in the breakwater project, and to coastal shipping for onward transit. They would pay a flat rate of 2s 6d per ton irrespective of distance for a volume averaging 8,000 tons per annum: a steady income of £1,000 a year for the company. This was ratified at a meeting of all the proprietors on 3 March 1821.
Alteration to the main route
On 26 December 1820 the engineer Stuart reported that Shillabear's route as far as Jump (later called Roborough) which ran via Fursdon was too steep for horse traction. He proposed a variation of the route on "Mr Archer's Land" that would reduce the gradient from 22" to 18" in the chain. (From 1 in 36 to 1 in 44; Kendall comments "as opposed to the estimated 1 in 72 maximum".) This required a further revision of the route immediately after obtaining the second act of Parliament, and after the letting of contracts for construction, and Stuart's report was unwelcome. Some embankment works near Roborough had already been undertaken. The committee held Stuart responsible and brought in Roger Hopkins as assistant engineer. In due course a new route with easier gradients was surveyed and approved; its course ran to the east of the earlier proposed route, but required a tunnel (Leigham Tunnel) and added a further £5,000 to the cost of the line. An act of Parliament, the (1 & 2 Geo. 4. c. cxxv), authorising this was passed on 2 July 1821. The total estimated cost thus became £40,000 and the length 25½ miles (41 km).
The new route needed to pass through the lands of the Earl of Morley, and he had a slatestone quarry at Cann; this was not far from the proposed line, but at a lower level in steeply sloping terrain, and the other side of the River Plym. He demanded a connection from the line to serve the quarry, and this was formally (but perhaps injudiciously) agreed to by three committee members on 6 June 1821 without reference to the full Committee. The connection might be a conventional branch line, or an incline crossing the Plym.
The engineer William Stuart engaged in a dispute with the committee over responsibility for the route selection, and was dismissed in October 1821. The contractor McIntosh was also dismissed amidst controversy over construction standards in June 1822, and Johnson Brothers (as successor to Johnson & Bryse) took over the work. Hopkins was now in charge as sole Engineer, he modified the specification for the later batch of rails; they were to be long, with lapped joints at the sleeper blocks.
Opening, and extensions The finances of the company during the construction phase had been extremely difficult, and work had only been kept going by repeated Exchequer Loans and other financial arrangements. There must therefore have been considerable relief when the line was opened on 26 September 1823 with a celebration breakfast. The opening was between Crabtree and the foot of Kings Tor, Walkhampton.Authorities are imprecise about the extent of the first opening. The most thorough works are probably Kendall, and also Shepherd, who on page 51 simply refers to "Opening Day" without indicating the extent. On the same page he says that "the extensions at each end of the line—to Sutton Pool in the south and to Princetown in the north—were completed in December 1825 and December 1826 respectively". However his map of the line on page 9 shows "original terminus of the line" at Crabtree. Dart, in "Devon Narrow Gauge" says on the page following plate 21, that "In 1825 the line was extended to Sutton Harbour, with a branch to Laira (Martin's) Wharf. The section from the quarries to Princetown opened in 1826." (Laira is on the Cattewater, a location also referred to.)
Dart reproduces part of a map prepared by J. C. Gillham which shows the line at Sutton Harbour (actually Bayly Wharf and Lockyer's Quay), forked and straddling "tidal mud"; this is labelled "Plymouth & Dartmoor Tramway Sutton Harbour Branch Opened 26 Sept 1823." The branch to "Laira Wharves" is marked "Terminus of Lee Moor Tramway" and "LMT opened 1825". In the caption to another map at plate XVII they say "When opened in 1823, the Plymouth & Dartmoor Railway ran both to Laira Wharf and Sutton Pool.”
Mitchell and Smith in "Branch Lines Around Plymouth", caption to map XVII, say "When opened in 1823, the Plymouth and Dartmoor Railway ran both to Laira Wharf and Sutton Pool.
Williams and Lee (in The Railway Magazine, March 1934), say that "From Sutton Pool, the Plymouth terminus, to King's Tor, a couple of miles short of Princetown, the line was opened with a procession on September 26, 1823".
Priestley writing in 1831 refers to the line running to "Crabtree in the parish of Egg Buckland, where it crosses the turnpike road from Plymouth to Exeter, and where the original line terminated".
As contracts were let in 1820 for the originally intended extent (from Crabtree) before the 1821 act of Parliament authorised the westward extensions, it might be concluded that the impecunious company opened to Crabtree first, in 1823, and extended to Sutton Harbour and Laira in 1825.
At the northern end, Shepherd refers to "the quarries" at Walkhampton; the King's Tor quarry was on the high ground within the northward loop of the line when later completed. Given the shortage of money it seems likely that the temporary northern terminus was on the approach to Kings Tor; there are indications on the earliest available Ordnance Survey map (1884) that support this.
The line followed a sinuous course to maintain a gentle falling gradient towards Plymouth: in a straight line the distance was . The track gauge was and the rails were bolted to cast iron chairs on stone blocks. The Leigham tunnel was long and there was one stone arch road bridge near Plym Bridge over the Roborough to Plympton road.