One of TRIPLET brothers

I'm posting a picture of a very special abnormal truck built and commissioned in the seventies.
This truck was part of a threesome handling a bridge carrier suspended on two multiple axle dollies.
Two of these tractors were pulling and one was pushing at the rear.
This majestic abnormal rig could transport a fabricated vessel or transformer weighing up to 300000kg, yes 300 ton!
Each of these tractors were powered by a 600HP Cummins engine.