DIVISION. That portion of a railroad assigned to the supervision of a Superintendent.

DOUBLE TRACK. Two main tracks, on one of which the current of traffic is in a specified direction, and on the other in the opposite direction.

DUAL CONTROL SWITCH. A power operated switch which is also equipped for hand throw operation.

DUMMY MAST. A short mast placed on top of a bracket post or bracketed to the side of a signal mast, to indicate another track between the bracket post or signal mast and the track or tracks for which signals are provided.

ENGINE. A unit propelled by any form of energy, or a combination of such units operated from a single control, used in train or yard service.

EXTRA TRAIN. A train not authorized by a time-table schedule. It may be designated:
Extra: For any extra train except work extra. 'Work Extra: For work train extra.

FIXED SIGNAL. A signal of fixed location indicating a condition affecting the movement of a train, such as train-order, interlocking, absolute or automatic block signal; switch; stop signs; yard limit signs or speed signs.

GRADE SIGNAL. An automatic home signal distinguished by a disk bearing the letter "G" on signal mast.

HOLIDAYS. When this term is used in timetables, timetable bulletins and train orders, it will apply to the following days: New Years Day, January 1st. Labor Day, first Monday in September Washington's Birthday, February 22nd. Thanksgiving Day, fourth Thursday in November. Decoration Day, May 30th Independence Day, July 4th. Christmas Day, December 25th.

HOME SIGNAL. A fixed signal at the entrance of a block or route to govern trains entering and using that route or block.

INTERLOCKING. An arrangement of signal appliances so interconnected that their movements must succeed each other in a predetermined order. It may be operated manually or automatically.

INTERLOCKING LIMITS. The tracks between the opposing home signals of an interlocking.

INTERLOCKING SIGNAL. A home signal of an interlocking.

MAIN TRACK. A track extending through yards and between stations, upon which trains are operated by timetable or train order or both, or the use of which is governed by signal indication.

OVERLAP POST. A post installed when necessary to mark the limit of control of a block signal.

PILOT. An employe assigned to a train when the engineer or conductor is not acquainted with the rules or portion of the railroad over which the train is to be moved.

REGULAR TRAIN. A train authorized by a timetable schedule.

SCHEDULE. That part of a timetable which precribes class, direction, number and movement for a regular train.

SECTION. One of two or more trains running on the same schedule displaying signals or for which signals are displayed.