This is a listing of some of the more common signals found in the New York City subway system. If you find any not listed that you've seen while riding the front of a train, drop me an E Mail to Joe Korman and I'll add it to this Web Page.
SIGNAL ATTRIBUTES - ASPECT & INDICATION
There are two major types of signals used in the subway -
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These signals are normally green and turn red after the FIRST CAR of the train the train passes it. Most of them have Green on top, Yellow in the middle and Red on the bottom. On some IRT lines the red and yellow are reversed. Diagram showing how signals work with the red signals behind the train and the position of the stop arms. |
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These signals can be generally identified as having two sets of colored signal lights. These signals control the movement of trains through track switches and are normally red. After the tower operator sets the track switches for the train, he/she clears the signal so the train may proceed. |
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All interlocking signals have a number plate like - The X denotes that this is an interlocking signal This signal is cleared by moving lever 14 to the LEFT. |
GIF of Union Turnpike Interlocking machine
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In addition both of these signals may further be GRADE TIME CONTROL, in that they will not turn yellow or green until the train has slowed to a pre-determined speed. Station Time signals allow a following train, under the designated speed limit, to enter a station as the leading train leaves. Without ST signals, the following train would have to wait outside the station until the leading train has left the station. |
All signals have a "TRIP STOP" which is in the raised or "TRIPPING"
position when the signal is RED. If the train operator tries to pass the signal
the
TRIP STOP will open a air valve called
the "TRIP COCK" on the subway car's TRUCK (the TRUCK is the part of the car
which holds the motors and wheels). The top of the tripper and the trip cock
are painted yellow so that if they are engaged, there will be telltale
strikemarks.
The open valve causes the train brakes to apply in EMERGENCY. The train brakes cannot be released again for about 20 seconds giving the train operator time to think about what he/she did wrong.
This is the color or combination of colors actually being displayed to the train operator.
This is the meaning of the signal to which the train operator must react.
To protect against malfunctioning signals displaying invalid aspects the RULE BOOK states that such signals are to be taken as its MOST restictive indication.
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Proceed |
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Proceed with caution next signal is RED |
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STOP radio for permission to pass |
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Grade time signal - signal will turn green if train slows down next signal is RED. Usually used on a down grade for an extended length of track. |
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Grade time signal - signal will turn green if train slows down next signal is RED and the track switch is set for DIVERGING ROUTE. |
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Grade time signal - usually used for a sharp curve where the train may get back to normal speed after passing the curve. |
The top head usually denotes the condition of the track ahead and the bottom head tells what for which route the track switches are set. The switch routes are classed as MAIN or DIVERGING, however there is no consistancy as to which is which. The train operator must know what signal aspects to accept at each interlocking signal. Although I show the X L14 plate in red, the actual signs in use today are black on white. The white on red, used on the old IRT signals are more colorful though.
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Proceed on MAIN ROUTE |
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Proceed with CAUTION on MAIN ROUTE |
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Time signal MAIN ROUTE If a 'D' appears in place of the 'S', it is a time signal MAIN ROUTE and the next interlocking is set for DIVERGING ROUTE |
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Proceed on DIVERGING ROUTE MAIN or DIVERGING On the BMT southbound at Dekalb Ave, before the reconstruction, a SB tunnel train had a BLUE lower head aspect for the bypass track. Green was to straight to Brighton and yellow was right to 4th Ave. At that time the SB trains were committed to branch after arriving in the station. Also the tunnel trains could bypass the station too. See DeKalb Ave for a track map. |
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Proceed with CAUTION on DIVERGING ROUTE |
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STOP AND STAY - call (radio or phone) for insructions if the signal does not clear after a few minutes. |
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STOP, push "CALL ON" button, look at track switch for proper route and proceed prepared to stop in half of your range of vision. Pushing the CALL ON button causes the TRIP STOP to move to the clear position allowing the train to move past it. Since the CALL ON signal is displayed by the tower operator and accepted by the train operator both are responsible for moving the train. This is a corrected display the call on light is yellow not white as previously shown. |
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This is a Train Order Signal that is used to tell a train operator any special instructions, such as re-route, local to express switch, or wrong-rail through tunnel. The White lights mean there are no orders. |
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This train order signal is telling the train operator to call 3111 for instructions. The telephone number is lighted as well as the red lights. |
GAP FILLERAdded at the suggestion of John H. |
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| Gap fillers are used 14th St - Union Sq and South Ferry (closed since 9-11-01). The Gap Fillers extend out from the platforms to bridge the space between the platform and the car body and door at the curved stations. When the train stops on the detector circuit, the Gap Fillers extend and signal turns red and is a Stop and Stay indication. After the train begins to move, the operator may not pass the GF signal until the red light is extinguished and the GF light is lit. The number or letter under the GF represent the track designation. In the samples below it is the for Track A of the two track South Ferry Loop. | |
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Stop and Stay. The Gap Filler is extended. |
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Proceed, Gap Filler has retracted. |
WHEEL DETECTORS |
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| Wheel Detector signals were installed at interlockings in 1996. They are designed to further enforce the speed at which a train travels through an interlocking. Most are only active if the switch is set to the diverging route. The train must remain under the speed limit until the WD END sign is reached. | |
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Sign at the start of the wheel detector section |
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Wheel detector off for your route. The switch is set for the main route. |
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Wheel detector on for your route and the train speed is within the speed limit |
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Wheel detector is active and the train is moving too fast. If the train doesn't slow down, the automatic stop arm will trip the train. |
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End of the wheel detection area |
OTHER JoeKorNer Subway Web Pages:
Saturday September 3, 2005
Copyright © 2005
by Joseph D.
Korman
