Two massive 131-ton electrical transformers left Dundee docks on Saturday morning on their way to a new substation at Tummel Bridge.
Loaded on lorries, the transformers were driven through the city under police escort to the dual carriageway to Perth.
Scottish Hydro Electric Transmission (SHE Transmission) moved the huge electrical devices as part of the Beauly to Denny network reinforcement project.
Similar units have already been delivered and installed successfully in Beauly and Fort Augustus as part of an essential upgrade to the electricity network.
Keith Inglis, SHE Transmission project manager, said: “Both transformers were constructed in Porto, Portugal, and have been shipped to the port at Dundee.
“We have employed an industry specialist to complete the last leg of the journey by road using a highly technical transport system,” he added.
He said because of the transformers’ weight and size they each needed to be moved on a 30m-long, 12-axle multi-steer trailer that could be manipulated to manoeuvre around obstacles at an average speed of just 10mph.
He added: “We would like to thank the local community for their patience whilst this essential equipment is delivered.”
The devices were so big that specialist haulier Alley Heavy Haulage was brought in to work alongside the police and roads authority to deliver both units with the minimum of disruption to other road users.
Niall Stuart, chief executive of Scottish Renewables, said: “The Beauly-Denny line is key to delivering Scotland’s renewable electricity targets and essential to connect wind, wave and tidal projects in the north of the country to the grid.”