Three 250-tonne Mercedes-Benz SLT tractor units have been used to transport what are believed to be the longest wind turbine blades ever moved by road in this country.

Leading the line for Bristol-based Plant Speed was an 8x4 Actros 4463 which arrived last month (November) via established partner City West Commercials.

The UK’s first new-generation SLT model, it has a range-topping GigaSpace cab and is equipped with innovative MirrorCam technology, as well as conventional mirrors.

Also drafted in were Plant Speed’s two Arocs eight-wheelers, both 4163 variants, while its Mercedes-Benz Sprinter vans performed escort duties.

The blades and their ‘spacer frames’ measured 68.25 metres in length and weighed around 24 tonnes each.

Unloaded from the vessel at Avonmouth Dock, they were then secured for transportation on Plant Speed’s purpose-designed, Nooteboom extendable Super Wing Carrier trailers.

The 24-mile journey to Magor, on the opposite, Monmouthshire bank of the Severn Estuary, took in stretches of the M5 and M4 – including the Prince of Wales Bridge – and was completed without incident in just an hour and 20 minutes.

“Good planning is key to a move of this nature,” explained Plant Speed managing director Paul Lomas (pictured).

“We’d undertaken a ‘dry run’ and worked through every aspect of the operation in fine detail beforehand, so that on the day it all ran like clockwork.”

Established by Lomas in 2003, Plant Speed runs a fleet of 16 trucks. In addition to the three SLTs, the line-up includes a pair of double-drive Arocs tractor units plated for operation at 180 and 120 tonnes GCW respectively, five 68-tonne Actros tractors with 6x2 tag axle configurations and an 8x2 drawbar rigid with crane.

All were supplied by City West Commercials, whose Avonmouth headquarters is less than five miles from its customer’s base in Hallen.

Plant Speed maintains its fleet in-house but relies on the dedicated Mercedes-Benz Trucks Dealer for the South West for warranty and technical support, and parts deliveries.

The latest SLT has replaced Plant Speed’s first 250-tonne truck, an Actros Titan which had been on the road since early 2013.

Like its two Arocs stablemates, the new Actros is powered by a top-rated, 15.6-litre in-line six-cylinder engine that produces 460 kW (625 hp).

While the Arocs are steel sprung, with the exception of its front axle the Actros rides on air.

Lomas said air suspension offered increased flexibility and finer control when picking up and dropping heavily laden trailers, and a weighing system that confirmed the loads over the second and two drive axles. “It just adds another level of safety,” he said.