Thameslink Programme - CTRL Enabling Works

Southdowns provided specialist advice to the main p-way design and build contractor during the CTRL enabling works.

The contractor was responsible for the replacement of a section of slab track within the Clerkenwell Tunnels over an Xmas blockade of the Thameslink Lines. The works entailed the use of heavy remote controlled breaking equipment within the tunnels beneath a densely populated section of London.

Southdowns was responsible for assessing the risk of damage to the ageing Victorian brick arch tunnels as well as identifying the likely area over which residents should be warned of potential groundborne noise and vibration during the works.

A comprehensive baseline vibration survey was conducted before the blockade commenced to record the existing levels of vibration currently introduced to the tunnel structures as a result of railway movements. Further measurements were conducted during a trial section.

The results were used to demonstrate that the breaking equipment was unlikley to generate levels greater than those already produced by railway movements. Groundborne noise measurements highlighted that a wide area of residents needed to be included in any public relations initiatives especially during night-time activities. Other work included input to the design of the proposed lineside electrification equipment to meet the project's noise standards.