By Christian Shelton15 October 2018
Heavy lift and transportation specialist ALE was comissioned to move two transformers, weighing 193 tonnes each, from the port of Inverness, to a substation in Tomatin, Scotland. The transformers were moved along a complex route using ALE’s AL34 girder frame with 24 axle lines of conventional trailer, two Trojan trucks and an additional prime mover. There were numerous structures on the route, including three onsite bridges. ALE said it selected this equipment to reduce the axle loadings, enabling safe transportation over them all.
According to ALE, all the bridges were assessed during the planning stages to ensure they could support the transport loads. The capacity of one bridge, however, could not be sufficiently determined so an alternative had to be found. ALE’s solution was to install an overbridge. A crane needed to be positioned a suitable distance from the centre of the bridge, so ALE chose a 100 tonne capacity wheeled mobile crane to install the 12 metre bridge raft over the bridge’s 9 m span.
Another challenge on the route was the range of steep gradients, both up and downhill. ALE transported the transformers over gradients of up to 14 percent. This was further complicated by road surfaces made up of loose materials.
As there is no limit to the number of prime movers that can be added to a convoy with the Trojans, ALE added a third prime mover for the transportation through Farr Windfarm. This route between the public highway and the substation was almost 18 km and its constant bends and varying gradients made it the most complex part of the transportation.
On the Trojan trucks, steering, braking, electrics, engine, and transmission are synchronised by a computer, enabling each to be matched across the vehicles and numerous elements to be controlled identically. ALE said this made them the most efficient vehicles to assist with traction during this section of the transportation.
ALE transported the transformers over 35 km before installing them at the substation with the operation being completed in 12 days.