[1] Many earlier designs required a very large turning radius; however, shrinking the width of the bed means decreasing the size of the load.
[1] The general solutions to this problem involved several modifications to the front-axle assembly.
The front axle assembly of a wagon consists of an axle, a pair of wheels and a round plate with a kingpin in its centre that sits halfway between the wheels, which may be mounted on spindles.
[2] A round plate with a hole in its centre is located on the underside of the wagon.
This technique eventually led to further designs well-adapted to narrow areas; the front wheels of express wagons, trolleys and floats are small enough to turn under the vehicle's body.