HEAVY haulage specialist Collett and Sons has completed the transportation and final installation of a 198Te transformer from Heysham Port to Gretna Grid Stability Facility.
Measuring 10.2m x 3.7m x 4.8m, the transformer was shunted within Heysham Port to a secure storage area utilising Collett’s 12-axle flattop trailer and lowered onto stools, ready for future transport.
As per the delivery schedule, Collett’s team returned to the storage area to start loading operations. Utilising a 24-axle 350-tonne capacity Scheuerle girder bridge trailer, the team built the trailer around the transformer. Once securely loaded and escorted by Lancashire Police, the team began the journey to Longtown.
Approximately halfway through the 88-mile route, escort duties were transferred to Cumbria Police. Given the weight of the cargo and its combined length of 77 metres with the girder bridge trailer, Collett explained how it executed several complex manoeuvres to ensure safe passage. Notably, the police halted motorway traffic to facilitate a planned manoeuvre, enabling the girder bridge trailer to contraflow on a joining slip road and bypass a weak bridge structure.
Due to the road conditions along the final four-mile journey not being suitable for accepting the negotiability of the girder frame trailer, the transformer was self-off-loaded onto temporary stools at a transshipment point in Longtown. The girder frame was then demobilised, and the transformer loaded onto a 16-axle SPMT (self-propelled modular transporter).
Collett project managers had to coordinate all preliminary works including applying for road permits, liaising with police authorities, highways authorities, local councils and conducting detailed route surveys. These efforts ensured clear passage by arranging tree trimming, cable diversions and outages, and temporary removal of street furniture along the route.
A structural analysis was done to verify if two bridge structures on the route, which dated back to the late 1800s, could support the combined weight of the SPMT and transformer. Just before the second bridge, named Corries Mill Bridge, the Collett team had arranged to temporarily stop and raise axles 2 and 15 on the trailer, to alter the weight distribution when crossing the bridge.
Upon arrival at the Gretna Grid Stability Facility, Collett’s scope of work included positioning the transformer onto its concrete foundation. Over the course of three days, the firm’s heavy lift team executed the final operation. It began with jacking up the transformer from the SPMT trailer to position a skid track underneath it. The transformer was then skidded along the track until it was jacked up once more to remove the skid track. Finally, it was carefully jacked down, ensuring precise placement onto the final plinth utilising positioning plates.
The delivery by Collett is part of a broader project to deliver to Gretna Grid Stability Facility, which also included the transportation of a 234Te Stator earlier in the year. This facility, equipped with a 60 MVA synchronous condenser, helps stabilise the grid by providing short-circuit and inertia power, along with reactive power compensation.
Eric Crosby, projects director at Collett & Sons, said, “The Gretna project required meticulous planning and coordination. We’re proud of our dedicated team for working extremely hard and providing a quality service to our customer. I’d also like to extend our gratitude to Lancashire and Cumbria Police for escorting the convoy, as well as to the local authorities and supporting service providers, whose assistance helped ensure a safe and smooth delivery.”
