The Canadian Government designing trucks
A sub story: How we came to having a truck manufacturing plant in Niagra, Ont.
Kennecott Copper developed a copper mine in Chile, and after it was on line, Chile nationalized the property. Kennecott said, "Fine, we'll leave. Just pay us the 84 million dollars we spent developing this mine." Chile wondered who they thought they were. After all Chile was a country, and they were just a company. So, Kennecott, that mere company, went to international court and seized every dime they had. So, they had to pay Kennecott.
After that was resolved Chile put in an order with us, Unit Rig, for half a dozen trucks. After production was started it was discovered Chile could not pay, so construction of the trucks was halted. They started shopping for financing and Canada agreed to finance the order providing 60 per cent of the production cost was spent in 'Canada. The plant was opened and we went on to produce many trucks in Canada, especially for Canadian and European delivery.
Anyway, back to the Canadian government, the truck designers: The drive train of the typical mining truck over seventy five tons was diesel/electric propulsion, similar to a locomotive. Hydraulic brakes was used up to about five mph, for maneuvering around the yard. For serious stopping up on the hill the braking was done by the dynamic brake system. What is was was a big bank of resistors on the deck, and when the dynamic brakes were applied the electric propulsion motors were converted to generators which fed thier output into the resistors which choked the motors in a magnetic field so strong they can't rotate. Simplified version.
The Canadian Government, bless their simple little hearts, decided that a fully loaded truck had to stop on a ten per cent down grade, using hydraulic service brakes alone.
The engineering nightmare was on.
The basic brake caliper design was from a B52 bomber, and by adding four more calipers, and two extra oversized rotors, we were finally able to get a truck to stop on a ten per cent grade.
The problem was that in normal production the average 200 ton truck was hauling berween 250 and 275 tons. Luckily we only had to guarantee the system to 200 tons.