At the western end of the tunnel, three reservoirs built between 1793 and 1866 feed the summit level.

Until the summit level was completed, little thought seems to have been given to water supply.

Two more plans were considered, and the third included extra reservoirs which would supply the summit level of the existing main line.

Miller in the lead, they stamped up the stone steps from the terrace to the summit level.

In 1938 the entire southern range of the summit level was declared as the military restricted area.

The summit level was completed in 1787, and became operational as soon as the tunnel opened.

The summit level emptied, causing floods in the town.

If not now, then during the discussions at summit level.

Traffic on the canal increased rapidly, and the summit level was lowered in the 1790s, cutting out three of the locks at each side.

Here, a high-altitude Lama helicopter was able to film at summit level.