August 24, 2019

Crossrail Anglia collaboration leads to isolation split innovation 

An integrated Crossrail team has come up with an innovative solution to the problem of moving equipment between work sites. The team from Network Rail, Costain and VGC Group collaborated to find a way for RRVs (road-rail vehicles) to travel under live overhead line equipment (OLE).

Because it is impractical to switch off too large an area of line, isolation splits are a recurring issue for complex rail jobs, requiring careful management of costs and time. As part of the £150m Crossrail north-east spur project, works on cable routes (protected channels for rail signalling equipment) required a series of isolation splits between Gidea Park and Crowlands in Essex.

The team, with input from Network Rail’s maintenance staff, carried out full risk assessments and produced a detailed project procedure which was accepted by Network Rail’s electrification and plant engineer. This allowed RRVs to travel under live overhead lines within possessions for this specific project.

Moving RRVs from one worksite to another involves travelling to the marker boards and informing the engineering supervisor that the machine will be leaving his worksite and travelling through the possession to a second worksite. Between worksites permission is sought from the PICOP for the machine to enter and travel through PICOP land. Before entering the second worksite permission is obtained from the second engineering supervisor.

By arranging to run RRVs to and from worksites under live overhead lines in this manner, better use can be made of resources with a consequent saving in costs.

“The Crossrail Anglia project has been running since 2014, and this is the first time a road rail vehicle has passed under a live overhead line,” said Jacques Kriel, VGC Rail Projects director. “It was a result of a successful collaboration between the Network Rail project team, principal contractor Costain, and VGC.”

Mike Condon, VGC Contracts Manager, thanked all those involved in setting up the process. “It’s very exciting to be working as part of an integrated team to develop new processes which we can use going forward to deliver this logistically complex project as efficiently as possible. I’m sure other projects will also benefit in the future.”

digging-social-DSC6669Overhead rail power lines carry 25,000 volts. It is important to maintain a safe working distance of at least 2.75 metres between plant and live equipment, so the power is usually switched off (called an ‘isolation’) while plant is moved between worksites. Sometimes rail equipment has to travel a long way to get to or between worksites, and that means the whole area must be made safe – however, it is impractical to switch off the power to too large an area of line. Therefore, engineers arrange isolation splits: separate isolation areas where the power is turned off. For complex rail jobs, where there are many people working on a busy rail route, planning these requires very careful management of safety, costs and time.

The VGC Group’s £2.3m contract with Costain is for the construction of three key sections of Crossrail’s north-east spur. The 16.4-mile section from Stratford, east London, to Shenfield in Essex will form one end of the eastern section of Crossrail.

VGC is undertaking the construction of the civil engineering works packages for sections”

  • Gidea Park PSP to Nags Head PSP;
  • Shenfield London end to country end of the project;
  • Shenfield London end PSP to Nags Head PSP.

This includes vegetation clearance, cable route works, bases for signalling equipment including principal supply points, signals, location cases, standard and staged FSPs. VGC teams will also install points heating bases, build walking routes and undertake electrical earthing.