Not a bad theory Pris, except for one detail that I probably should have included: the two 'Towers (hey, that sounds like a good title for a movie!) were on different seats, at least 3m (10ft) apart, on different sides of the aisle. Unless Sis Ruth in her senility was wandering around the whole train, sitting down and then getting up, leaving a different 'Tower behind each time, I just don't understand it!
Myself: you're not wrong! I've always suspected that a confluence of strange forces have come together to form a vortex around the New South Wales State Rail Authority...