Truck Features

Loose engineering


It’s unusual for a road transport engineer’s son to follow in his father’s footsteps, but that’s exactly what long-serving engineer Chris Loose has done, working for a number of heavy truck OEMs over many years. Chris’s father, Rex, was a regional engineer with Mobil in the 1970s.



Chris Loose contacted Historic Vehicles about a couple of engineering landmarks his father had achieved in the mid-1970s: one being a then-advanced rigid with two-tanker road train and the other being a design for an electro-mechanical braking system, specifically for long-combination vehicles.

The road train was based on a 10×4 Atkinson twin-steer rigid truck, fitted with hub-reduction tandem drive axles and a lazy fifth axle. Maximum loading was assured by having widely-spaced tri-axles on the two tanker trailers, to comply with bridge formula restrictions.

The Mobil road train ran from Darwin to Tennant Creek and Alice Springs, hauling 

20,500 gallons (93,000 litres) of fuel, with a gross mass of 92.5-102 tonnes, depending on the product being transported.

The rig measured 145 feet (44.2 metres) overall and rolled on 56 tyres. A 330hp engine – big power back then – ensured a cruising speed of 88.5 km/h. It cost the princely sum of $120,000 on the road (around $1,500,000 in today’s money).

Rex Loose’s experience with road trains showed him that braking performance was less than ideal, given the delay in air brake operation along the length of  road train. He determined to rectify that situation and worked on an electro-mechanical solution that was explained in an SAE paper, dated July/August 1975.

It makes interesting reading, even today:


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