The present invention relates to remotely controlled apparatus that may be moved horizontally to any predetermined location with respect to a tube sheet of a nuclear steam generator to view the inside of a particular tube connected thereto and to actuate equipment necessary for the maintenance of the tubes. Since a nuclear steam generator is usually highly radioactive and thus generally unavailable for close observation or repair, this apparatus is provided to permit an operator to make remote observation and repair of such a steam generator as viewed by a periscopic device through a standard television monitor.