From Here to There: Designing Transportation

From Here to There: Designing Transportation — page 3
The wheel was the crowning achievement in the early history of transportation But it was the invention of the axle that made it so useful An axle is the rod or spindle that goes through the center of a wheel or group of wheels which allows them to rotate axle axle A simple axle between two wheels was the first engineered land transportation vehicle Putting wheels on carts and buggies presented a new challenge Transportation routes needed to be widened and strengthened to bear the size and 6