The Challenge:

Brighton Mainline is a key commuter line, quadruple track for much of its length, historically operated by a simplified Bi-Directional signalling system. Where only a single track was available only one train could pass in the reverse direction every 10 minutes.

Passing traffic in both directions meant the capacity was at best three trains per hour either way. In addition to signalling operating issues, the poor condition of Balcombe Tunnel meant that major works were required. Solutions were needed to keep the service running smoothly during periods of ‘reverse’ working.

The nature of the line, with many rail connections on flat junctions, means it is very susceptible to delays. Train operations required six trains per hour, minimum, in each direction utilising one line. Kier was awarded the project to install the Westplex system, replacing all main lineside cables in the long bidirectional section between Keymer Junction and Preston Park.

The Solution:

Kier provided full bidirectional working between Balcombe Junction and Haywards Heath. This resulted in a significant operational improvement on the BML under perturbed working and was a welcomed success. Kier replaced nine 650V power feeders and cabling with new incoming feeding arrangement FSR’s and FSPs. Each FSR was designed to each Substation, saving valuable programme time and money. All 650V feeders were fitted with insulation monitoring units, monitored by Intelligent.

The Westplex equipment is a safety-critical microprocessor-based data transmission system designed to interface directly with signalling relays and provides a positive impact on sustainability, maintenance and train operations.

By installing Westplex, all the lineside main cable is replaced with a 6pr telecoms cable which transmits signalling controls and indications safely via the Westplex transmission system. The existing lineside infrastructure is maintained and controlled from the Westplex modules. In the event of cable failure, diversity is provided through the FTN system.

The Impact:

Increased operational reliability was achieved on BML through renewal of trackside signalling equipment such as replacing existing Reed track circuits & AC track circuits with EBI200 track circuits; recovery of redundant IBJ's; replacing filament type signal heads with Dorman LED type and replacement of multicore cables with Westplex transmission system. The new Dorman LED signal heads offer increased reliability, ease of maintenance, and lower fault attendance. Standardising these signal types presents a better profile to drivers.

One of the key benefits of Westplex is that the system configuration data is stored in an EEPROM within the interconnecting connector, allowing the maintainer to replace modules without the need for the downloading/configuring of site-specific configuration data. This provides faster fault rectification time and reduces spares holding requirements. These improvements on the BML, especially completing the introduction of Westplex, will provide a more resilient signalling system for years to come.

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