the incline was bypassed in 1848. On July 20, 1837, the Camden Incline, between Euston and Primrose Hill on the London and Birmingham Railway opened. A Pit fishbelly gravitational railway operated between 1831 and 1846 to service the Australian Agricultural Company coal mine. B Pit opened 1837 and C Pit opened mid-1842. All were private-operations by the same company. Inclines The majority of inclines were used in industrial settings, predominantly in quarries and mines, or to ship bulk goods over a barrier ridgeline as the Allegheny Portage Railroad and the Ashley Planes feeder railway shipped coal from the Pennsylvania Canal/Susquehanna basin via Mountain Top to the Lehigh Canal in the Delaware River Basin. The Welsh slate industry made extensive use of gravity balance and water balance inclines to connect quarry galleries and underground chambers with the mills where slate was processed. Examples of substantial inclines were found in the quarries feeding the Ffestiniog Railway, the Talyllyn Railway and the Corris Railway amongst others. The Ashley Planes were used to transship heavy cargo over the Lehigh-Susquehanna drainage divide for over a hundred years and became uneconomic only when average locomotive traction engines became heavy and powerful enough that could haul long consists at speed past such obstructions yard to yard faster, even if the more roundabout route added mileage. Operation Level tracks are arranged above and below the gradient to allow wagons to be moved onto the incline either singly or in short rakes of two or more. On the incline itself the tracks may be interlaced to reduce the width of land needed. This requires use of gauntlet track: either a single track of two rails, or a three-rail track where trains share a common rail; at the centre of the incline there will be a passing track to allow the ascending and descending trains to pass each other. Railway workers attach the cable to the upper wagon, and detach it when it arrives at the other end of the incline. Generally, special-purpose safety couplings are used rather than the ordinary wagon couplings. The cables may be guided between the rails on the incline by a series of rollers so that they do not fall across the rail where they would be damaged by the wheels on the wagons. Occasionally inclines were used to move locomotives between levels, but these were comparatively rare as it was normally cheaper to provide