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Inspired by the need to reduce the cost of a resignalling project in the Midlands, senior design engineer Tahir Ayub was given the time by Network Rail to formulate a plan, followed by a year of developing the safety case and two years of working to develop and implement new Network Rail standards and technology.

He was supported by project engineer Ernest Brigden, as part of the signalling national innovation group within IP Signalling.

The work done to drive the project encouraged Network Rail’s suppliers - 12 different companies in this instance - to innovate and develop new technologies. In fact, those technologies could find outlets in other fields, such as double-insulated streetlamps and even switchgear for electric car chargers.

After trials using the prototype equipment at the Leicester signalling test site, the use of class 2 equipment has now been approved and is ready for rollout across the network. Crossrail, Reading, Watford, Stafford and Wolverhampton resignalling projects are early adaptors to the class 2 based distribution system.

Class 2 cable is a generic term for enhanced unarmoured cable. This new cable provides enhanced mechanical protection, rodent protection (through the use of fibre weave) and security protection, utilising Network Rail identifiers.

A polycarbonate and coating solution was developed to insulate associated equipment, such as switchgear, transformers and signal housings.

Savings from the use of class 2 cable – new standard NR/L2/ELP/27408:

* Weight and cost of copper

* Transport;

* Cost of laying cables

* Time and complexity of design (class 2 does not require earth fault analysis or touch voltage control)

* Less cable contingency ( cable contingency is a cost placed on the cost of cable in case of theft or damage)

* Fewer power supply points required on large schemes

* No need to place the equipment outside the overhead line equipment fall zone

Sample figure: typical cost of 3-core 95mm cable: £20.68 per metre

Typical cost enhanced unarmoured cable 95mm cable: £14.13per metre. A saving of 32 per cent.

The Newport resignalling scheme was used as a test case in building the business case for this project. It was calculated that a saving of £1m would have been achieved in the delivery of the project’s power renewals.

SUPPLIERS

Following the endorsement of the safety case Network Rail issued four new standards detailing the design, construction, installation and test of Class II based signalling power distribution systems. The supply chain was engaged to deliver the new range of products with much of the development costs borne by them. The following suppliers have been actively engaged with Network Rail through the Class II Technology Introduction process:

Transformers: Signalling Solution Limited; Invensys and Trans-Tronic

Rectifiers: Signalling Solution Limited, Invensys, Trans-Tronic

Power Cable: Cleveland Cable, Anixter cable, Eland Cable, Apex Cable

Low Voltage Switchgear: Schneider Electric, CSE Ltd, Henry Williams, Ilecsys, MGB, and Traix.

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