“Linbrooke and Fujikura worked together to meet Network Rail’s stringent specifications in far from ideal conditions. Over the course of the project, the partnership managed to drastically increase the reliability of machinery and, in turn, reduced operational costs and improved profitability.”

Mick Carter, Engineering Manager (Operational Comms), Linbrooke


As the owner and infrastructure manager of most of Britain’s rail network, Network Rail is constantly adapting its infrastructure to ensure safety and efficiency for an ever increasing number of passengers across an expanding network.

As part of these ongoing improvements, Network Rail constructed a Fixed Telecommunications Network (FTN) to provide a platform to support its Global System for Mobile communications – Rail (GSM-R) network and operational railway circuits across England, Scotland and Wales. The upgrade has resulted in all operational railway circuits, information technology data and business telephony traffic being migrated to the FTN.

This large-scale task involved upgrading 16,000km of telecoms cable and installing a completely new fibre optic and copper network for the Synchronous Digital Hierarchy (SDH) transmission and the new GSM-R train radio system to run on.

Linbrooke – renowned for delivering outstanding mission critical solutions in telecoms, power and signalling in Rail, Utilities and Subsea environments – was entrusted with installing, splicing, terminating and testing circa 5,000km of fibre on the FTN network.


With the unique setting of a trackside environment, the installation of high specification spliced fibre optics was very difficult.

Open to the elements and all weather conditions, dusty and punctuated with damp tunnels, conducting major improvements in a trackside environment is notoriously challenging. The jointers involved in the improvements were also very restricted in terms of time, due to the importance of reopening main rail routes as quickly as possible, which allowed minimal time for remedial work.

On top of this, Network  Rail set a target specification at the start of the project of better than 0.05 dB maximum splice loss, at a time when the maximum losses outlined by the industry was 0.15 dB. Achieving a loss of no more than 0.05 dB is straightforward in a clean room but it was considered incredibly difficult – if not impossible – to achieve at the trackside. In dirty, challenging surroundings, Linbrooke had to find a way to install a great length of fibre optic cable, while controlling costs and keeping the number of costly site revisits to a minimum.


To overcome the challenges involved in the FTN upgrade, Linbrooke teamed up with Fujikura, which provided equipment, such as splicing machines and cleaving tools, as well as technical support for the project.

Fujikura provided Linbrooke with cleaving tools and fusion splicers from the FSM-30S through to the latest model – the 70S – and provided full after sales technical support and training through the duration of the improvements.

Equipment and hardware was updated over the course of the project – along with constant updates to splicer software – to suit the task at hand. Fujikura also provided Linbrooke with technical support and advice on all aspects of the equipment involved. This included cleaning, maintenance, achieving the optimal splicing routine and assistance with spreading CAPEX across all new machinery. Due to the training delivered by Fujikura on the treating and cleaning of hardware – alongside the continual development of the hardware itself – the reliability of the equipment improved noticeably over the course of the project.


Due to the productive and efficient partnership between Linbrooke and Fujikura, Network  Rail’s stringent specification of better than 0.05dB maximum splice loss was successfully achieved on 100% of installed joints, despite challenging terrain and conditions.

Over the course of the eight year project, the rate of revisits to remediate splices reduced dramatically from 15% to less than 3% due to improved machine performance. This was a direct result of the high level of training and maintenance provided to Linbrooke by Fujikura.

The increase in hardware reliability and efficiency translated into reduced CAPEX on machine maintenance and replacement, ensuring increased profitability for Linbrooke over the course of the project.