Case Studies

Fieldwork Case Study

Traction Supply Earthing and Bonding Survey

New trains with much higher performance than those now being used are to be introduced on London Underground’s Metropolitan, District, Hammersmith & City and Circle Lines. The new fleet will operate from a number of existing depots and sidings.

To enable the new trains to operate at full performance, the traction power system and associated electrical track equipment must first be reinforced to support the increased electrical load. At the same time, it is convenient to make changes to the depot electrical systems to improve flexibility and safety. As these systems have evolved and grown over many years (the depot was opened in 1906) it was necessary to identify, survey and record the existing earthing and bonding arrangements and it was by no means possible to anticipate what would be found.

Fifth Dimension was engaged to plan and undertake physical surveys at Hammersmith depot and produce a detailed report which identified the size, type and condition of the existing earthing and bonding arrangements. This information was supplemented with full CAD drawings and photographs.

The challenge was to complete the trackside element of the work within a single weekend possession, the rest of the depot buildings being surveyed during the week to a set timescale.

Fifth Dimension used experienced site technicians to produce method statements and carry out risk assessments and then undertake the physical elements of the survey, with the site data assessed by an engineer familiar with London Underground electrical assets. Our in-house CAD team produced the required drawings.

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