A 198-tonne transformer has made its way from Heysham Port to the Gretna Grid Stability Facility, thanks to a highly orchestrated heavy transport operation led by UK firm Collett & Sons Ltd.
The transformer, measuring 10.2 metres long, 3.7 metres wide, and 4.8 metres high, was first received at Heysham Port. It was initially moved using a 12-axle flattop trailer and placed on storage stools. That was just the start. When delivery time came, Collett returned with a 24-axle Scheuerle girder bridge trailer—capable of handling 350 tonnes—and built the rig around the transformer, reducing cargo handling and improving safety.
The 88-mile journey to Longtown involved more than just wheels and roads. With a convoy escorted first by Lancashire Police, then handed off to Cumbria Police midway at Junction 39 of the M6, the oversized load demanded precision coordination. At one critical point, traffic was halted so the transporter could reverse into a slip road and bypass a weak motorway bridge—a planned detour that required contraflow movement on live roads.
The final stretch posed even greater challenges. The last four miles weren’t suitable for the girder trailer due to tight road constraints. Collett executed a mid-route transshipment at Longtown. The transformer was offloaded onto temporary stools, then repositioned onto a 16-axle Self-Propelled Modular Transporter (SPMT) for the last leg. With its 360-degree steering and precise control at a crawl-speed of 1 mph, the SPMT navigated the narrow path to Gretna.
Pre-planning was exhaustive. Collett’s project managers secured permits, conducted route surveys, and coordinated with local councils, police, and utility services. Overhead cables were lifted, trees trimmed, and street furniture temporarily removed. Two Victorian-era bridges on the route were subjected to structural analysis. Before crossing one of them—Corries Mill bridge—axles 2 and 15 on the trailer were raised to shift the load distribution, a method signed off by consulting engineers and highway authorities.
At the site, the final job wasn’t simply parking the unit. Collett’s heavy lift crew took three days to position the transformer on its concrete foundation. The process involved jacking up the unit, sliding it along a skid track, and using positioning plates to set it precisely on its plinth.
This delivery was part of a larger effort at the Gretna facility, which earlier received a 234-tonne stator. The site houses a 60 MVA synchronous condenser, a key player in the National Grid ESO’s Stability Pathfinder programme—built to help balance the UK power grid as it shifts toward renewables.
“The Gretna project required meticulous planning and coordination,” said Eric Crosby, Projects Director at Collett & Sons. “We’re proud of our dedicated team for working extremely hard and providing a quality service to our customer.”
