Tipton Tunnel
The need for a tunnel to enable road traffic to flow unhindered by the trains has been long over due
Martin O'Keeffe sent me this item from " New Civil Engineer" as the rail runs so close to the canal & Caggies Boat Yard was affected by the excavations he was sure you would be interested to read exactly how it all took place
The removal of the last level crossing on the West Coast Main Line is now well underway after the successful installation of a Box-Jacked underpass in Tipton.
BAM Nuttall installed the 6,500 ton concrete box without hitch over the Easter weekend, handing back possesion of the railway to Network Rail two and a half hours early.
Over the weekend 250 people were used to shift 6,500m3 of muck and inject 23m3 (28tons) of grout.
Sandwell Metropolitan Borough Council first started trying to get rid of the crossing in the 1950's. It is believed to be the last such crossing on the West Coast Main Line and its road barriers are down for an incredible 45 minuted in every hour as a succession of high speed and local commuter trains whip by. This is hardly ideal for encouraging business into Tipton.
A 101 hour possession started on Good Friday and the jack had to be finished when it ended on Easter Monday. As a result the box had to march forward at 2.5meters to 3 meters an hour.
As soon as the overhead power lines were turned off, workers sprang into action: track was lifted, ballast removed, and excavators moved into position to start digging out ahead of the box. The box was driven along by three jacks, each connected top and bottom to its rear end. Prestressed Macalloy bars held the jacks in place at the top, each carrying 91 ton load.
Despite the need for speed, care and precision was required as the overhead catenaries and cables remained in place. Lubrication was also all important. Steel ropes were fed along the underside of the box to help it slide, with four "treads" each with 128 ropes. In addition, bentonite was injected along the sides of the box through nozzles between the box wall and the excavated face. After jacking was completed, the bentonite was expelled with grout, which also fixed the box in place.
Martin
