A way cover section is shaped with a continuous lateral arc by pre-stressing so that its top panel has a radius in its top panel from one side panel of the cover section to the other. A wiper at the leading edge of the cover sections that may also serve as a bumper. The wiper has an elastomeric wiper section at one end and an elastomeric bumper section at the other end, with an intermediate section of a harder and more lubricious material that fits on a rolled over edge of the cover section to which the wiper is attached.