Craig wrote:

Maybe as other mass transit systems use, eg, New York, a hard rigid
plastic. Still comfortable to sit on given that you are only on it
briefly !!! and not holding hidden all kinds of gunk that must be
embedded in the fabric.....

One model of London bus was fitted out with the back 4 or 5 rows
upstairs in solid plastic - it makes them have a very unpleasant feel -
almost unsafe. Like the screens protecting the drivers, the only
reason they were there is because they were necessary. This doesn't
lead to a feeling of safety.

Perhaps a good hybrid would be to have easily replaceable covers (but
NOT easy to remove without suitable tools!) over a plastic-covered
sprung or sponge seat?

Neil