Yes, I've always loved the paternosters. The I.G. Farben building in Frankfurt had them. The Farben Building used to be Headquarters for the US Army's Fifth Corps when V Corps was in Frankfurt (it moved to Heidelberg in the 1990s), and Americans found the paternosters fascinating. It's really an efficient way of moving people. (I hoped to find a website that showed a picture of one, but couldn't locate one.)

And yes, there were accidents. Most caused by stupidity - in some cases from people scrambling to get out because of the false belief that the "little cubicle" in which one was lifted or lowered actually turned over when it reached the top or bottom. (It doesn't - picture an endless chain-link belt with the cubicle attached at its top to the axle of the link itself; as the belt rotates the cubicle travels alongside the belt and pivots on the connection to the axle when the link reaches top or bottom. Thus the "bottom" of the cubicle remains the floor no matter whether the cubicle is going up or down, and it is completely safe to ride "around" the cycle. The powers that be finally had to post signs in the cubicles saying it was safe to ride them around.)

But the most fascinating thing about the Farben Building, if what I was told is true, is the rotunda (which was used as a cafeteria when the building was V Corps Headquarters in the 1960s and 1970s at least). When the Farben Building was built, circa 1925 IIRC, the domed interior ceiling of the rotunda was covered with a thin layer of one of the most precious metals then known to man. Guess what it was.