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►RAILROAD SIGNALS of the U.S.
PRIMER ON
AMERICAN RAILROAD SIGNALS
Glossary of Signal Terminology
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RAILFAN GUIDES HOME
RAILROAD SIGNALS HOME
CHAP 1 -
Introduction
CHAP 2 -
Some Basic Specs
CHAP 3
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Glossary of Signal Terminology
CHAP 4
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Reading And Interpreting
Railroad Signals 1
CHAP 5
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Reading And Interpreting
Railroad Signals 2
Unless noted, the definitions used in this section
come from a C&O/B&O rulebook, dated April 27, 1969.
Other rulebooks
quoted are:
Baltimore and Ohio Railroad -- April 26,
1953 (B&O/53)
CCOR Consolidated Code of Operating
Rules - October 1, 1980 (see below)
CSX
Transportation -- January 1, 1987 (CSX)
New York
Central System -- January 1, 1951 (NYC)
Pennsylvania
Railroad - April 26, 1925
Uniform Code of Operating
Rules -- 1962 (UCOR)
While various rulebooks choose to group definitions of similar topics together, instead of alphabetically, I have chosen to alphabetize my list, placing Manual Block System way far away from Automatic Block System.
It's interesting to note the change in some definitions from the "same" railroad thru the years, for instance: B&O/53, C&O/B&O/69, and CSX/87.
Also, without the benefit of being able to read thru many different rulebooks, you wonder why one railroad defines CTC, and another does not, or why they all don't fully describe the terms relating to interlocking. Curious.
Terms used in a description that are in italics are defined elsewhere.
While some may feel that it is tedious having multiple definitions for the same term, it may also help to squelch disagreements between two people when they can't agree on a definition because they learned the rule from a different book. I hope this helps.
A quick speed look-up (this is a guide
as given speeds are not absolute, and may vary by railroad):
45 Limited
30
Medium
15/20 Slow
15/20 Restricted (most RR's used
15 up till the mid 70's, and then changed it to 20 to save fuel)
Absolute Block -- A section of track which may be occupied by only one train or engine at a time.
Absolute Block Section -- The section of track between opposing absolute block signals, at least one block in length, on a track signaled in both directions.
Absolute Permissive Block (APB) System -- An automatic block signal system for a track signaled in both directions on which a train or engine causes a STOP indication to be displayed on the next opposing absolute block signal and STOP or STOP AND PROCEED on signal in rear of the train. Signal indications do not supersede the superiority of trains, therefore, Timetable or Train Order authority is required. Todd Sestero
Absolute Signal -- A block or interlocking signal without a number plate, the most restrictive indication of which is STOP. also see Block signal, Dwarf signal, Interlocking signal, CPL signal, Fixed signal
Absolute Signal (CCOR) -- A block or interlocking signal designated by an "A" marker, or by the absence of a number plate.
Approach Signal (CCOR) -- A fixed signal used to govern the approach to another signal.
Approach Signal (UCOR) -- A fixed signal used in connection with one or more signals to govern the approach thereto.
Aspect -- see Signal Aspect
Automatic Block Signal (ABS) System -- A series of consecutive blocks governed by block signals (UCOR and CCOR add "cab signals, or both"), actuated by a train, engine, or by certain conditions affecting the use of a block.
Automatic Block Signal (ABS) System (CSX) -- A series of consecutive blocks whose use is governed either by block signals actuated by a train or by certain conditions affecting the use of a block. Unless so specified, such signals do not authorize the movement of trains.
Automatic Cab Signal System (ACS) (CCOR) -- A system which provides for the automatic operation of the cab signal and cab warning whistle.
Automatic Interlocking (CCOR) -- An interlocking actuated automatically by the approach of a train or engine.
Automatic Railroad Crossing System -- An arrangement of fixed signals and signal appliances so interconnected that the movement of trains or engines over the crossing are automatically controlled.
Block (CCOR) -- A length of defined limits, the use of which by trains and engines is governed by block signals, cab signals, or both.
Block -- In Automatic Block Signal Territory, the length of track between two signals in the same direction, the use of which by trains or engines, is governed by an automatic block or interlocking signal.
Block -- In Manual Block Territory, the length of track between designated points or between open train order offices, the condition of which will be given as prescribed by the rules.
Block (CSX) -- A length of track of defined limits. In signaled territory, a block is the length of track either between two consecutive block signals governing movements in the same direction or from a block signal to the end of signaled territory.
Block Indicator (UCOR) -- A device located at hand operated or spring switches to indicate track occupancy in the block or blocks to which it refers.
Block Signal -- A fixed signal at the entrance of a block to govern trains and engines entering and using that block. also see Absolute signal, Dwarf signal, Interlocking signal, CPL signal, Fixed signal Todd Sestero
Cab Signal (UCOR/CCOR is close) -- A signal located in engineman's compartment or cab, indicating a condition affecting the movement of a train or engine and used in conjunction with interlocking or block signals, or in lieu of block signals. Note: Special instructions will be used to govern the operation of cab signals where in use.
Centralized Traffic Control (CTC) (CCOR) -- A block signal system under which train or engine movements are authorized by block signals whose indications supercede the superiority of trains for both opposing and following movements on the same track.
Centralized Traffic Control (CTC) (UCOR) -- A system in ABS territory under which train or engine movements are authorized by block signals, whose indications supercede the superiority of trains for both opposing and following movements on the same track.
Color Position Light (CPL) Signal -- A fixed signal in which the indications are given by color and the position of two or more lights. It consists of a cluster of lights normally displayed in pairs. For some indications, marker lights are displayed above or below the main cluster to qualify its meaning. also see Absolute signal, Block signal, Dwarf signal, Interlocking signal, Fixed signal
Communicating Station (NYC) -- A station where an operator or signalman is on duty or where a trainman may communicate by telephone with a train dispatcher, signalman or operator.
Control Operator (CCOR) -- An employee assigned to operate a CTC or interlocking control machine.
Control Siding (CCOR) -- A siding, the entrance to which is governed by signal indication.
Current of Traffic -- The movement of trains on a main track, in one direction, specified by the rules.
Distant Signal (PRR/25) -- A fixed signal used in connection with one or more signals to govern the approach thereto.
Division -- A portion of a railway or railroad designated by timetable. also see Subdivision Todd Sestero
Division (or Area) (UCOR/CCOR//PRR/25) -- That portion of a railway assigned to the supervision of a Superintendent or other designated officer.
Driver (PRR/25)-- The employee in charge of and responsible for the operation of a track car as prescribed by the rules.
Double Track (CCOR//PRR/25) -- Two main tracks, upon one of which the current of traffic is in a specified direction, and upon the other in the opposite direction.
Dual - Control Switch -- A power-operated switch which is also equipped with a hand-throw lever for hand operation.
Dual Control Switch (CCOR) -- A power-operated switch which, by use of a selector lever and a hand throw lever, may be hand operated.
Dwarf Signal (B&O/53//PRR/25) -- A low home signal. also see Absolute signal, Block signal, CPL signal, Interlocking signal, Fixed signal
Electric Switch Lock (UCOR) -- An electric lock connected with a hand operated switch to prevent its operation until the lock is released.
Electrically Locked Switch -- A hand-operated switch with an electrically-operated locking appliance.
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.
Engine (NYC) -- A machine propelled by any form of energy and used in train or yard service.
Engine (PRR/25) -- Any self-propelled unit used for the movement of trains.
Engineman (UCOR) -- The employee in charge of and responsible for the operation of an engine.
Engineman (PPR/25) -- The employee in charge of and responsible for the operation of an engine as prescribed by the rules.
Extra Train -- A train not authorized by a timetable schedule. It may be designated as, EXTRA or WORK EXTRA. see Train
Extra Train (UCOR) -- A train not authorized by a timetable schedule. see Train Todd Sestero
Extra Train (PRR/25) -- A train not authorized by a
timetable schedule. It must be designated
as:
Extra - for any extra train except passenger train extra or
work train extra;
Passenger Extra - for passenger train
extra;
Work Extra - for work train extra.
Extra Train (NYC) -- A train not authorized by a timetable
schedule. It may be designated as:
Extra - for any
extra train, except work extra;
Work Extra - for work train
extra.
Extra Train (CCOR)
-- A train not authorized by a timetable
schedule. It may be designated as:
Extra - for any
extra train except work extra;
Work Extra - for an extra train
authorized by Form H train order.
Facing Point Lock, Spring Switch (CCOR) -- A locking device for a spring switch which automatically locks the points in normal position.
Fixed Signal -- A signal of fixed location indicating a condition affecting the movement of a train or engine. also see Absolute signal, Block signal, Dwarf signal, Interlocking signal, CPL signal
Fixed Signal (NYC/CCOR) -- A signal of fixed location indicating a condition affecting the movement of a train. Note to definition of Fixed Signal: The definition of a "Fixed Signal" covers such signals as switch, train order, block, interlocking, semaphore, disc, ball, stop boards, yard limit boards, speed boards or other means for displaying indications that govern the movement of a train. CCOR's note to the above description is: Note.-The definition of a "Fixed Signal" as switch, train order, block, interlocking, such signs as stop signs, yard limit signs, reduce speed and resume speed signs, and other other means for displaying indications that govern the movement of a train.
Grade Signal (UCOR) -- A stop and proceed signal equipped with a marker displaying the letter "G".
Home Signal (B&O/53//PRR/25) -- A fixed signal at the entrance of a route or block to govern trains or engines entering and using that route or block.
Interlocking -- An arrangement of fixed signals and signal appliances so interconnected that their movements must succeed each other in proper sequence and for which interlocking rules are in effect. CCOR adds: It may be operated manually or automatically.
Interlocking Limits (CCOR) -- The tracks between the outer opposing absolute signals of an interlocking.
Interlocking Limits (UCOR) -- The tracks between the extreme or outer opposing interlocking signals of an interlocking.
Interlocking Signal (UCOR) -- A fixed signal at the entrance to or within interlocking limits to govern the use of the routes.
Interlocking Signals (CCOR) -- The fixed signals of an interlocking.
Interlocking Station (UCOR) -- A place from which an interlocking is operated (aka: tower - Todd).
Intermediate Signal (B&O/53) -- An automatic block signal equipped with a number board. Todd Sestero
Indication -- see Signal Indication
Interlocking Limits -- The tracks between the opposing absolute signals governing entrance to an interlocking.
Initial Station (UCOR) -- The station at which a schedule is first timed on any subdivision is the initial station for that schedule, and for an extra train it is the station at which such train is created.
Limited Speed -- A speed not exceeding 45 MPH also see Maximum Authorized speed, Medium speed, Slow speed, Restricted speed
Main Track -- One or more than one track designated by special instructions extending through yards and between stations, upon which trains are operated by timetable, train orders, block signals, interlocking signals, rules or special instructions, and under the supervision of the Train Dispatcher unless otherwise provided. also see Single track, Two or More tracks
Main Track (CCOR//PRR/25) -- A track, other than an auxiliary track, extending through yards and between stations, upon which trains are operated by time table or train order, or both, or the use of which is governed by block signals.
Main Track (UCOR) -- A track extending through yards and between stations, upon which trains are operated by time table or train order, or both, or the use of which is governed by block signals, interlocking signals, or other method of control.
Manual Block System -- A system used for the blocking of trains moving in the same direction and for which manual block system rules are in effect.
Manual Interlocking (CCOR) -- An interlocking operated by an employee by means of an interlocking machine.
Maximum Authorized Speed -- The maximum speed authorized by special instructions, for a subdivision or portion of a subdivision. also see Limited speed, Medium speed, Slow speed, Restricted speed
Medium Speed -- One half maximum authorized speed, but not exceeding 30 MPH. also see Limited speed, Maximum Authorized speed, Slow speed, Restricted speed
Motor Car (NYC) -- A car propelled by any form of energy and used in train or yard service. Todd Sestero
Passing Siding -- A track auxiliary to the main track designated by special instructions for meeting or passing trains.
Pilot -- Am employee assigned to a train when the Engineer or Conductor, or both, are not fully acquainted with the physical characteristics or rules of the railroad, or portion of the railroad, over which the train is to be moved.
Reduced Speed (CCOR) -- Proceed prepared to stop short of train, engine, obstruction
Register Station (CCOR/UCOR) -- A station at which a train register is located.
Regular Train -- A train authorized by a timetable schedule. also see Train, Extra train, Superior train, Train of Superior Right, Train of Superior Class, Train of Superior Direction
Remote Control (B&O/53) -- A term applied to a method of operating outlying switch and signal appliances from a stated point.
Restricted Speed -- Proceed preparing to stop short of train, obstruction, or anything that may require the speed to be reduced, but not exceeding 15 MPH also see Limited Speed, Maximum Authorized speed, Medium speed, Slow speed
Restricted Speed (B&O/53) -- Proceed, prepared to stop short of: train, obstruction, improperly lined switch, or broken rail.
Restricted Speed (CCOR) -- Proceed prepared to stop short of train, engine, obstruction, or switch not properly lined, looking out for broken rail or anything that may require speed of a train or engine to be reduced, but not exceeding 20MPH.
Route (UCOR) -- The tracks a train or engine may use in passing from one point to another. Todd Sestero
Schedule (UCOR) -- That part of a time table which prescribes class, direction, number and movement for a regular train.
Section (CCOR/NYC) -- One of two or more trains running on the same schedule displaying signals or for which signals are displayed.
Semi-Automatic Signal (B&O/53) -- A signal having both manual and track circuit control.
Siding (NYC//PRR/25) -- A track auxiliary to the main track for meeting or passing trains. CCOR adds: The timetable will indicate stations at which sidings are located.
Siding (UCOR) -- A track auxiliary to the main track for meeting and passing trains. Sidings and their capacities will be designated in the time table or special instructions.
Signal Aspect -- The appearance of a fixed signal conveying an indication, as seen from the direction of the approaching train or engine.
Signal Aspect (CCOR) -- The appearance of a fixed signal conveying an indication, as viewed from the direction of the approaching train, or the appearance of a cab signal conveying an indication as viewed by the observer in the cab.
Single Track (NYC) -- A main track upon which trains are operated in both directions. also see Two or More tracks, Main track
Schedule -- That part of a timetable which prescribes class, direction, number and movement for a regular train.
Signal Indication -- The information conveyed by the aspect of the signal.
Signal Indication (UCOR) -- The information conveyed by a fixed signal or cab signal. Todd Sestero
Single Direction Signal System (SDSS) -- An automatic block signal system under which trains or engines are operated with the current of traffic under Rule D-251.
Slow Speed -- One half maximum authorized speed, but not exceeding 15 MPH also see Limited Speed, Maximum Authorized speed, Medium speed, Restricted speed
Slow Speed (B&O/53) -- A speed not exceeding 15 MPH.
Spring Switch -- A switch equipped with a spring mechanism arranged to restore the switch points to normal position after having been trailed through.
Station -- A place designated by name on the timetable, or by special instruction, or a designated place at which a train may stop for traffic, or to enter or leave the main track.
Station (CCOR) -- A place designated in the timetable by name.
Station (NYC//PRR/25) -- A place designated on the timetable by name, at which a train may stop for traffic; or to enter or leave the main track; or from which fixed signals are operated.
Station Protection Signal (UCOR) -- A stop and proceed signal equipped with a marker displaying the letters "SPS", used to protect trains or engines occupying the main track in yards or at stations in the block protected by the signal.
Subdivision -- A portion of a Division designated by timetable. also see Division
Superior Train -- A train having precedence over another train. also see Train, Extra train, Regular train, Train of Superior Right, Train of Superior Class, Train of Superior Direction
Terminating Station (UCOR) -- The station at which a schedule is last timed on any subdivision is the terminating station for that schedule, and for an extra train (except work extras) it is the station to which such train is authorized.
Three or More Tracks (CCOR) -- Three or more tracks upon any of which the current of traffic may be in either specified direction.
Timetable -- The authority for the movement of trains subject to the rules. It may contain classified schedules with special instructions relating to the movement of trains, engines, equipment, and other essential information.
Timetable (NYC) -- The authority for the movement of regular trains subject to the rules. It contains the classified schedules of trains, with special instructions relating thereto.
Traffic Control System (TCS) -- An automatic block signaling system under which trains or engines are operated in either direction on one or more tracks under Rule 271.
Track Car (PRR/25) -- A self propelled car or truck which may be manually moved to or from the tracks.
Train -- An engine or more than one engine coupled, with or without cars, displaying markers. also see Extra train, Regular train, Superior train, Train of Superior Right, Train of Superior Class, Train of Superior Direction Todd Sestero
Train (NYC) -- An engine or motor car or more than one engine or motor car coupled, with or without cars, displaying markers. also see Extra train, Regular train, Superior train, Train of Superior Right, Train of Superior Class, Train of Superior Direction
Train of Superior Right -- A train given precedence by train order. also see Train, Extra train, Regular train, Superior train, Train of Superior Class, Train of Superior Direction
Train of Superior Class -- A train given precedence by timetable. also see Train, Extra train, Regular train, Superior train, Train of Superior Right, Train of Superior Direction
Train of Superior Direction -- A train given precedence in the direction specified by timetable as between opposing trains of the same class. also see Train, Extra train, Regular train, Superior train, Train of Superior Class, Train of Superior Right
Train Order Signal (UCOR) -- A fixed signal provided at train order offices used in conjunction with the delivery of train orders and as prescribed by Rule 91A.
Train Order Signal (PRR/25) -- A signal displayed in the place provided therefore, in addition to a fixed signal, when there are orders either to hold or to be delivered to a train.
Train Register -- A book or form which may be used at designated stations for the registering the time of arrival and departure of trains and such other information as may be prescribed.
Train Register (NYC) -- A book or form which may be used at designated stations for registering signals displayed, the time of arrival and departure of trains and such other information as may be prescribed.
Two or More Tracks (NYC) -- Two or more main tracks upon which any of the current traffic may be in either specified direction. also see Single track, Main track
Yard (CCOR) -- A system of tracks within defined limits over which movements not authorized by timetable, or by train order, may be made, subject to prescribed signals and rules, or special instructions.
Yard (NYC//PRR/25) -- A system of tracks within defined limits provided for the making up of trains, storing of cars and other purposes, over which movements not authorized by timetable, or by train order, may be made, subject to prescribed signals and rules, or special instructions.
Yard Engine (CCOR) -- An engine assigned to yard service.
Yard Engine (NYC//PRR/25) -- An engine assigned to yard service and working within yard limits. Todd Sestero
Thanks to Michael Watnoski for the use of many of the rulebooks I picked this info out of.
If you see additional terms which are not listed here, or are described differently from what is listed here, please scan the appropriate page(s) and email them to me..... Thanx..... Contact info is here
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NEW 9/11/2005
Last Modified
26-Aug-2013