An alternative overhead system: the Rigid Overhead Conductor-rail System
A Rigid Overhead Conductor-rail System (ROCS) can be used at stations for improved electrical clearances and has several advantages over conventional tensioned overhead equipment (OHE). Ankur Saxena, Engineering Manager at Furrer+Frey, explores further.
The costs of the recent UK mainline electrification projects have attracted much adverse publicity, resulting in delays to projects and the cancellation of future electrification projects. A look at the way electrification infrastructure projects spent their budgets shows that a major chunk of overall cost was associated with achieving 25kV electrification on the existing Victorian infrastructure. A lot of stations, bridges and tunnels cannot achieve compliant electrical clearances required for a 25kV electrification system as they were never designed to accommodate electrified stock in the first place.
In all recent electrification projects, be it the Edinburgh Glasgow Improvement Programme (EGIP) in Scotland or the Great Western (GW) electrification project in England and Wales; designers and delivery partners faced great challenges in delivering a 25kV overhead system that respects the required electrical clearances from existing infrastructure.
This was not an easy problem to solve, as designers either have to go for an expensive, bespoke arrangement to maintain the clearances or go for derogation i.e. permit smaller clearances where justified by a CSM RA compliant risk assessment (in accordance with Railway Group Standard GL/RT1210 AC Energy Subsystem and Interfaces to Rolling Stock Subsystem which contains the UK national technical rules mandated by ENE TSI).