Tuesday, 9 August 2011

The Tunnel

Today, work started in earnest on construction of the tunnel. The site was dug out, hardcore tamped in, and a level bed of conctrete laid. This will provide support for two rows of two building blocks, with a space beween them for the tunnel lining. The blocks will support removable paving slabs at the surface of the path.

On emerging from  the tunnel, the line will curve round to the left.

The tunnel construction site.
Having started tunnel construction, there is a need to get it finished as soon as possible to allow the path to be re-opened. Hence, today the removable treads and their supports were installed, and made good for tomorrow's predicted rain. With the engine in front of it it appears much bigger than necessary, but it will be better when it is landscaped and the portals fitted.

A short construction train simmers by the tunnel entrance, while a mechanical digger prepares the site.
The tunnel trackbed was in place today, and temporary track was again laid to ensure levels and gradients appeared correct. 9F no 92203 had the honour of heading the test train, with the portal (part detailed and unpainted) and a retaining wall in place. These are based on the south portal of Combe Down tunnel, Bath. The change of gradient from 1 in 50 to about 1 in 100 in the tunnel is clearly visible in the picture. It's perhaps rather sudden and will be smoothed in in the final trackwork.

A 9F emerges from the tunnel with a train.

(Sunday 21/8) The track is now laid through the tunnel, the tunnel liner is in place and the cavities filled with foam, and some outside landscaping is complete.


A 4F takes a train into the tunnel.

Penny assists with load-testing of the path over the tunnel.

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