Structural role of the chair rail?
I was wondering if the chair rail plays a role in stiffening the walls of a bus, or whether it is literally there only to support the chairs bolted to it. I am curious about this because I am planning a floor repair job that will leave the walls unsupported by the floor for about a ten-foot span between the fuel tank tube (back right) and a spot about three feet in front of the wheel wells (the rusted floor here will be entirely cut away).
I am worried that the walls will have a tendency to droop, counteracted only by the stiffness provided by the outer siding and the windows (which may be sufficient, I dunno). The chair rail will be intact over this span on both sides and would normally add stiffness, but it is mostly cut away for the wheel wells. Do I perhaps need to weld a long plate to the channels just above the wheel wells, to compensate for the wheel well cutouts in the chair rails?