gave rise to the line's reputation as the toughest main line in Britain due to its constant curves and continuous steep gradients. The climb to Whitrope was more challenging than that to the summit of the West Coast line at Beattock due to its curvature. From , the line proceeded south via Portobello East Junction towards the Moorfoots and the Lammermuirs, following the valleys of the South Esk, Gore Water and the Tyne. From Hardengreen Junction near there began a climb at a gradient of 1 in 70 to reach Falahill, before meandering along the course of the Gala Water down to its confluence with the River Tweed, which accompanied the line for a few miles eastwards to Melrose and St Boswells, descending at typically 1 in 150. The route swung to the south-west at St Boswells towards the River Teviot and on to Hawick, where the valley of Slitrig Water provided easy going before the climb at 1 in 70 over the massed hills to Whitrope Summit. The gradient subsequently eased to 1 in 96 through Whitrope Tunnel to Whitrope Siding box and descended at an unbroken 1 in 75 for over through the curves necessitated by the rugged countryside around Arnton Fell towards Riccarton Junction and Steele Road. Then came easier terrain in the form of Liddel Water, where the line turned west to follow Liddesdale and the Esk valley to reach the border at Kershope Burn. The final stretch from Riddings struck out across the coastal plain to Longtown and then Carlisle. The first sod on the Border Union Railway was turned at Hawick on 22 July 1859, a day after the line had received Parliamentary approval. Construction works were to last two years and ten months; the task was made all the more difficult by the Caledonian Railway's delaying tactics in Parliament, which meant that the main works could only begin as winter was approaching. The heavy construction work took place in difficult weather – three frightful winters and two wet summers – in desolate country miles from public roads, which required teams of horses to bring materials across the moors and hillsides to the remote work sites. Life on the moorland was hard for the railway navvies and it was difficult to hire and keep men in the very wet conditions which at times prevented any progress. When the NBR's directors toured the Hawick-Hermitage section