130km Fibre Installation, Welwyn to Slough


Client appointed JSM to deliver a new network build for their client. JSM delivered this complex project in its entirety including surveys, redesign, construction, fibre installation and testing.




10 Months

Date Completed

February 2019

The route, approximately 130 km long, traversed 4x London Boroughs, Hertfordshire, Buckinghamshire, and Slough Borough Council.  It also crossed a number of structures and land belonging to CRT, Network Rail, LUL and TfL, requiring extensive stakeholder management and negotiations to obtain the required permits and licences to cross their properties and structures.

Due to its length, the route was divided into 9 spans to optimise the programming and delivery of the project.  Our planning department surveyed and reviewed the whole route identifying along the route any opportunity for redesigning the route to reduce the delivery timescales, minimise disruption and/ or avoid difficult structures or properties, for example belonging to Network Rail.

Key Project Deliverables

  • Civils — trial holes, excavations, backfill reinstatements in verges, footways and carriageways,  HDD on some spans of the route, JSM installed  1 new 110mm duct. JSM built  473 pulling and joint chambers; Traffic Management including specialist TM;  Installation along canal towpaths;
  • Canal towpath works including providing and managing works on barges and managing access to towpaths on pontoons;
  • Cable installation — 130km of 432 fibre optic cable  (loose tube);
  • Installation and splicing of 64 joints approximately every 2 kms;
  • Test result packages consisting of Chromatic Dispersion (CD) and 1550nm Polarisation Mode Dispersion (PMD) Testing;
  • Successfully managed over 100 Special Engineering Difficulties (SEDs).

Special Engineering Difficulties (SEDs) Management

  • Along the route nearly 100 SEDs including bridge structures, culverts, rail lines and canals presented their own unique challenges requiring specific engineering solutions.
  • Trial holes were required to ensure buildability in or around these structures or find alternatives solutions;
  • A redesign was required to avoid programme delays caused by the proposed use of third party networks. Alternative routes were supplied to ensure programme delivery on all spans.
  • Overall all challenges were successfully managed through redesign and strong negotiations skills and JSM’s ability to adapt the programme of works.

Stakeholder Management

  • The 130 km diverse route between Welwyn, LB Hillingdon and Slough crossed structures owned by Network Rail, Highways England, TfL, LUL and the Canals & River Trust (CRT). JSM ensured the buy in of all stakeholders, meeting them weekly, addressing any concerns they had and keeping them informed at every stage of the project.

Services Provided

  • Surveys and route proving
  • Civils
  • Chambers build
  • Duct supply and Installation
  • Duct roping
  • 432f Fibre Installation
  • Splicing and testing
  • Project Management
  • Permits and notices
  • Traffic Management
  • Risk Management
  • Stakeholder Management
  • As built drawings