This seems like it has potential for being the core of an interesting interview question. Maybe something along the lines of "You are hired as the Chief Shunter

This seems like it has potential for being the core of an interesting interview question. Maybe something along the lines of "You are hired as the Chief Shunter (lol) of a new rail company and the CEO, to cut costs, has stated that only half of all cars will have toilets. What instructions will you give the shunters? What complications could arise? What is the optimal solution and how would it impact UX?" etc. etc.