Walthers medusa cement co. structure

Greetings,
Can anyone tell me what type of trucks were used to ship the powdered material to local ready-mix plants to be mixed with sand, aggregates (crushed rock and stone) and water to produce concrete.
Walthers assembly instruction sheet mentions that cement was shipped by trucks but fails to mention what type of trucks - appreciate and and all answers re above. Thank
Keep on trackin
Rudy Montreal Canada