An infopanel found at the site
Mentioned: River Tyne, River Team (Causey Burn)
Construction of the arch began in 1725, built to transport coal from the Tanfield coal mines to the River Tyne for shipment to other parts of the country. The arch was built for a group of coal-owning families who dominated the collieries on Tyneside and became known as the "Grand Allies". They commissioned local stone mason Ralph Wood to attempt the building of the grand structure. A daunting task! At the time neither he, nor anyone else in the world had experience of building such a huge railway bridge. The arch spans a gorge over the Causey Burn, It consists of a series of stone arches, with the tallest arch standing at 24 meters high, making it the highest stone arch in the world at the time of its construction. Designed to support a track for horse-drawn wagons, which were used to transport coal from the mines across the gorge. The wagons would travel along the track on wooden rails, which were supported by stone sleepers laid across the arches.
Construction of Causey Arch presented several difficulties for Ralph Wood. The bridge had to span a steep gorge and the ground on either side of the gorge was uneven, rocky, and unstable. This made it difficult to construct a stable foundation for the bridge. Ralph Wood used wooden beams to create a timber frame that was then covered with stone blocks. The timber frame acted as a temporary support during the construction of the bridge, and it helped to distribute the weight of the structure evenly across the stone piers. Once the stone blocks were in place and the mortar had hardened, the timber frame was removed, and the bridge was able to stand on its own.
The aim of the arch was to carry wagons of coal from Tanfield collieries to the main wagonways on the River Tyne. Two tracks of wooden rails crossed the arch: one to take the coal to the river and the other to return empty wagons. In its heyday 930 horse drawn wagons crossed the bridge in each direction daily making it that so every 20 seconds a wagon would have gone by. Only 45 metres on average would have existed between each wagon and the one following it, making the whole site a hive of industrial activity!