While the discharge of toilets directly onto the tracks is potentially unpleasant,
Extremely unpleasant if you are a track-worker standing in the cess when a discharging toilet on a HST▸ (High Speed Train) goes by, particularly if on the outside of a curve.
I remember reading somewhere about a photter who'd also been subject to a short sharp shower of sh1t whilst standing next to an occupation crossing gate on a max speed section of the ECML▸ (East Coast Main Line), again on the outside of a curve. I think it happened to him more than once. I think I'd've learnt after the first shower not to stand so close to the line when a HST was approaching!