Such trains still required the usage of two conductors; it was not till September 1958 that they began working using only one conductor. Prior to this modification, it had been essential to station a conductor in every automobile of a prepare to operate doorways prior to the arrival of MUDC. Exterior guard lights needed to be added to all vehicles on all divisions outfitted with MUDC (Multiple Unit Door Control). The modification involved connecting 9 level jumpers between vehicles to cross alo...