Pin puller In the old days of hump yard operation, men manually pulled the pin and uncouple cars as they slowly topped the hump. It’s still done that way today, only the pin puller is also the remote operator for the locomotives shoving long strings of cars too. At North Platte, Nebraska’s, Bailey Yard East Hump, a pin puller is about to send a tank car into the bowl on May 3, 2011.