Glasgow to Carlisle road (1825)
Dumfries & Galloway, Lanarkshire and Cumbria, UK
date 1814 - 1825
era Georgian |
category Road |
ICE reference number HEW 2438
The original mail road that ran between Glasgow and Carlisle was built by the turnpike trusts that controlled it, and it was upgraded by engineer Thomas Telford in the 19th century. Some of his bridge structures and toll houses remain, though the modern M74, A74(M) and M6 motorways have superseded the route.
Parts of the original route followed the line of Roman roads. By 1814, this strategic inter-city transport link had become "nearly impassable". Thomas Telford’s (1757-1834) chief assistant William Alexander Provis (1792-1870) surveyed the route in 1814-15, and the subsequent improvements they devised were implemented by 1825.
The resulting Glasgow to Carlisle Road was the Georgian equivalent of a modern motorway, reducing the original distance from 165km to 150km. The route headed east out of Glasgow, south east through Lanarkshire, Dumfries & Galloway and into north Cumbria, via Gretna on the Scotland-England border, to Carlisle. It followed generally along the line of the present-day A72, B7078, A702, B7076 and M6 roads.
The original mail road had been tolled and this continued with the new road. The turnpike trusts were allowed to retain control of an 18km length between Glasgow and Hamilton and a 21km stretch over the boundary of Lanarkshire and Dumfries & Galloway. The remaining 111km were reconstructed or refurbished under Telford’s direction, in his capacity as Engineer to the Highland Roads & Bridges Commission. The total cost was around £50,000.
The new road’s longitudinal elevation ranged from near sea level to nearly 305m above it at the Beattock summit. A ruling gradient of not steeper than 1 in 30 was adopted, involving extensive cut-and-fill and 15 large bridges.
The general specification called for the main carriageway to be 5.5m wide, to allow two mail coaches to pass, with a crossfall of 1 in 30 from the centreline. Its construction consisted of Telford’s traditional hand-pitched bottom course of 180mm high stones topped by 180mm of broken stones less than 63mm in diameter. The roadway had a 2.4m wide extension on each side covered in gravel for use by horse and pedestrians, beyond which were the all-important side drains. The whole width of 10.4m was compacted with a heavy iron roller.
The enabling Act of Parliament for the road provided for not less than 10 broken-stone depots per 1.6km (1 mile). A single man maintained a length of between 1.6km and 8km, depending upon its level of usage. In winter, the men were employed in keeping the road clear of mud and water. In summer they removed loose surface stones, filled potholes, cleared drains and repaired retaining walls.
Of the 15 bridges, the most unusual was a three-span cast iron arch bridge over the River Esk at Metal Bridge in Cumbria. It was built in 1820 with a southern span of 45.7m adjoining two spans of 32m. The northernmost span was probably added during construction to provide additional drainage for floodwater, hence the asymmetric elevation. The ironwork was prefabricated to Telford’s standard lattice spandrel design. The bridge closed to traffic in 1911 and was replaced with a ferro-concrete structure in 1913-6, which was itself replaced by the existing reinforced concrete bridge in 1970.
Masonry bridges of note along the route include single arch structures over the River Avon at Hamilton (24.8m span, constructed 1823-5), over Glengonnar Water at Abington (9.1m span, built 1824-5), over the River Clyde at Elvanfoot (27.4m span, constructed 1824-5), over Evan Water at Beattock (12.2m span, built 1819) and over the River Annan at Johnstonebridge (24.4m span). There was also a bridge with three arches of some 9m span over the River Nethan at Milton Bridge near Lesmahagow, which was replaced in 1938 by a three-span steel bridge.
There were eight toll houses along the road — at Hamilton, Kirkmuirhill, Lesmahagow, Douglas Mill, Abington, Beattock, Dinwoodie and Gretna. Only the ones at Hamilton, Dinwoodie and Gretna survive — Dinwoodie Toll House (NY104901, see map) being the best-preserved example of Telford's standard design, and a Category A listed building. Gretna Toll House (NY327671) was the venue for runaway marriages from about 1830 until well into the 20th century, though it is now a tearoom.
Assistant engineer: William Alexander Provis
Contractor (Beattock Bridge, Dinwoodie Tolhouse): John MacDonald
Contractor (Abington and Elvanfoot bridges): John Park
Ironwork (1825 Esk Bridge): William Hazledine