There must be an engineer here who can answer this dogday question. I notice that of all the splendid inventions of our time, the one that seems to be down the most is the escalator. Everywhere I go, escalators are stopped, barricaded off, in pieces with guys working on them. The same is true of those moving staircases. Can anyone shed light on this? Are we dealing with an invention with so many moving parts that it just breaks down a lot? An invention that hasn't had any improvements since 1910? Overambition? Just curious

(famous Canadian poem quote: "This elevator does not work on Ascension Day")

yours, Peter T.