Alan's point is very relevant here. Another very important fact is that when flushed the contents of the toilet would land on the coach bogies of the coaches, especially the MK11, MK111's. Although not a particularly pleasant topic it shouldn't be discounted. Several shades of brown should do the trick . I would never have known only a guide on an IRRS tour of Inchicore mentioned it to a chap who was about to put his hand on one of the bogies on a MK11 aircon during the visit. That is seriously informative reading in those posts J, your knowledge and enthusiasm for sharing it are really important and hugely appreciated.
Rich,