Whiteball Tunnel

Rail South has recently completed repairs to the Whiteball tunnel, in Devon, on behalf of Network Rail.  Situated on the Paddington to Plymouth Station line, the tunnel is 1094 yards long and built to accommodate 2 tracks of Brunel's broad gauge.   

Client:Network Rail
Value:£1.1M
Location:Devon

The tunnel suffers from increasing areas of delaminating brickwork and deep open joints compounded by considerable water ingress within the tunnel lining.

Standard methods of repair are proving to be of low productivity and limited effectiveness given the constraints of tunnel access. The tunnel is on a 3 monthly sensitive examination regime and deterioration is occurring faster than standard repairs can be implemented. 

Amco and Donaldson Associates were therefore tasked by Network Rail to carry out a Condition Survey and Options report, followed by the development of a repair design to Form A and B with AFC drawings.

The evaluation criteria utilised included capital cost, maintenance cost over 25 years, the effect on rail traffic, constructability and technical performance. Four main options were identified and subjected to a comparative assessment options review using the design criteria. The Ramarch system was selected for the tunnel repairs as it offered intimate support to the tunnel lining thus ensuring brickwork could not fall out onto the operational railway. The Ramarch was considered innovative, satisfied the technical performance requirements and was also economically viable. Following approval Amco were deployed to carry out the tunnel repairs utilising the Ramarch system. 6 in number repair areas were identified totalling 355 linear meters. The project team quickly developed bespoke Ramarch lifting frames and access platforms for the delivery of the contract works which facilitated the safe and efficient construction and erection of the Ram arch.

The works were carried out utilising two construction teams each shift, each team consisting of 9 operatives. The repairs were successfully carried out, accident and incident free, over six 48 hour weekend abnormal possessions.