really hard seats on the new walk-through carriage trains

I am finding the seats on the newer through-carriage trains on my daily commute to and from Kingston to Waterloo too uncomfortable and can feel the effects even now one day later. Can anything be done? I can't always carry a cushion - luckily I had a towel on me the other night and sat on that but several times a week I have to carry other bulky stuff so can't come prepared.