. Operation of trains and station work and telegraphy . ses occur where itis desirable to allow several trains to follow each othera block at short intervals. This may be done by the useof the permissive system/ which consists of an attach-ment to the absolute machine at each end of the sectionwith one permissive staff; this instrument is shown inFigure 128. To use it; an absolute staff is withdrawn from the in-strument at X and is used as a key with which to un-lock the base containing the permissive staff to be re-moved, which action locks the absolute staff in the per-missive attachment unt
. Operation of trains and station work and telegraphy . ses occur where itis desirable to allow several trains to follow each othera block at short intervals. This may be done by the useof the permissive system/ which consists of an attach-ment to the absolute machine at each end of the sectionwith one permissive staff; this instrument is shown inFigure 128. To use it; an absolute staff is withdrawn from the in-strument at X and is used as a key with which to un-lock the base containing the permissive staff to be re-moved, which action locks the absolute staff in the per-missive attachment until the permissive staff is permissive staff is a steel rod and eleven removablerings, any of which will authorize a train to pass throughthe section to Y. If less than twelve trains are to fol-low each other, the last one takes the remaining ringsand the rod. When all the rings are received at Ythe operator returns them to the permissive staff, placesit in the permissive attachment or base, and locks it by 408 RULES FOR MOVEMENT OF TRAINS.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadtrains, booky
