MIDLANDS MAIN LINE UPGRADE

SPL Powerlines UK

Enable Infrastructure has made a substantial contribution to the Midland Main Line Upgrade, which is considered the largest improvement program for the line since its completion in the 1870s. Enable Infrastructure was contracted by SPL Powerlines UK to operate at various locations along the Midland Main Line (MML) spanning over 100 miles. Our highly skilled Enable Power Systems team offered their specialised knowledge, while our civils team executed the construction work. Conditions on the ground were sometimes challenging – our teams faced snow, rain and frost – but we persevered to keep the project moving to schedule. 

 

The initial phase of the upgrade consisted of the recently finished Network Rail London to Corby (L2C) Electrification Project. SPL Powerlines UK’s contract worth £300m for this project entailed electrifying 192 km of single track. This encompassed 350 design submissions, over 2,300 foundations, 3,240 overhead line equipment (OLE) structures, the setup of eight substations, a total of around 900 km of wire (OLE, Return Screening Conductor [RSC], fibre, LV/HV), and a total steelwork length for OLE structures of 38 km. 

A crucial aspect of Enable Infrastructure’s efforts was cable routeing and installation. In total, we laid over 220,000 meters of HV (25kV) and red bond cable, utilizing both manual labour and road rail vehicles (RRVs). We implemented a variety of solutions including Trough-Tec Systems, elevated Schneider Electric GRP, raised Arco GRP, concrete troughing, buried route containment for the new 25kV HV cables, and bonding cabling. The project encompassed Under Road Crossings (URX), Under Track Crossings (UTX), and Over Track Crossings (OTX). 

  • Need to interface with other contractors on site and other third parties, such as National Grid 
  • Geographical challenge of working across a distance exceeding 100 miles, while simultaneously managing multiple sites. 
  • Multidiscipline challenge, with Enable Infrastructure working as a tier 2 contractor to SPL Power Lines UK over disciplines including S&T, P&D, civils, T&C, and design 
  • Working to a client design programme, where there were, on occasion, issues that made elements of the programme unfeasible for installation. 

To prevent congestion and ensure smooth construction and electrical tasks, we conducted weekly interface meetings and dilapidation surveys. Enable Infrastructure devised a logistical plan to minimise fleet mileage, project costs, and environmental impact. This involved reducing carbon emissions through the use of a shared project van and optimizing material movements for efficient deliveries.  

Our multidisciplinary team effectively collaborated, ensuring no skill gaps and enabling us to deliver the project on budget, on time, and accident-free. Leveraging our extensive knowledge and experience, Enable Infrastructure provided design solutions that improved build times and resulted in cost savings for the client. 

Following the successful completion of the L2C project, which included our separate project for Amey to deliver four platform extensions at Kettering Station, the Office of Rail and Road (ORR) approved the new ‘Energy Subsystem using the United Kingdom Master series overhead contact system’ for L2C in April 2021. In the aftermath of finishing L2C, Enable Infrastructure proceeded with the construction of a National Grid 400kV-to-25kV supply point substation near Braybrooke, just outside Market Harborough in rural Leicestershire.  

Work commenced on farmland in October 2021, with the winter season involving the removal of trackside scrub, a ‘reduce dig’ to level the cleared land, and the creation of a 400mm-thick concrete pad measuring 29.9 x 4.1 meters for the 400kV substation. One of the most remarkable aspects of the project was the substantial amount of spoil – nearly 5,000 tonnes! – that had to be excavated and relocated during the process. 

  • Installation of a distribution network operator (DNO) unit, of a glass-reinforced plastic (GRP) yellow handrail and a GRP post route as crucial adjuncts to the substation 
  • Construction of traction power building reinforced concrete (RC) foundation 
  • Construction of external stairs & ramp, inclusive of handrail 
  • Supply and installation of hardstanding 
  • Supply and installation of type 1 walkway around hardstanding 
  • Construction of crane turning area hard standing 
  • Installation of six 4-way XL multiduct buried routes from SGT1 & SGT2 
  • Installation of Cubis Ultima chambers 
  • Installation of four 150mm-diameter multicore cable ducts 
  • Installation of Cubis Stakka Boxes 
  • Installation of four URXs (approx. 12mtrs each) 
  • Installation of 3.0-high hot-dip galvanised palisade fencing 
  • Installation of 1.8m-wide 3.0m high palisade access gate 
  • Installation of Cubis Stakka chambers 
  • Installation of twenty 160mm-diameter rigid coil power ducts buried route from HV chambers to the traction power building 
  • Installation of C1/9 traction bonding route 
  • Installation of traction bonding 
  • Installation of four 19/4 22mm RSC 
  • Installation of a full 150m earthing farm, including eleven augured earth rods at 6,000mm

Gallery

“The safe and professional manner of all work prior to the night, followed by the safe and smooth organisation for the lift, highlights the wonderful collaboration between SPL Powerlines UK and Enable Infrastructure.” - Tom Walker, P+D Project Manager for SPL Powerlines UK

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