Box Tunnel

Brunel begins sinking exploratory shafts to examine the geology along the proposed route through Box Hill.

Work begins on Box Tunnel through Box Hill for the Great Western Railway.

Difficult rock strata and heavy water ingress delay excavation, with less than half of the tunnel completed.

The railhead at Chippenham served as an interim endpoint pending the completion of the line through Box Tunnel.

The railway approaches toward Box Tunnel carried trains eastward from Bath on the completed main line.

Opening the Box Tunnel completed the route through the hills east of Bath and connected the Avon valley to Chippenham.

The western entrance is finished with a more elaborate architectural treatment than the simpler eastern portal.

Brunel pushes the main contractor to increase the Box Tunnel workforce from about twelve hundred to four thousand men.

Opening the long Box Tunnel connected Chippenham by rail with Bath and the Bristol section beyond.

The opposing tunnel workings meet with an alignment error of less than two inches and construction is completed.

Box Tunnel opens as the longest railway tunnel in the world at the time.