Signal School Session 2

a roadway signal operated automatically or manually at the entrance to a block. This statement is the definition of a:

Block Signal

and automatic block signal system is a series of consecutive blocks governed by block signals cab signals or both actuated by a _ or by certain conditions affecting the use of a block.

train

in a 2-block, 3-aspect system, a green aspect indicates the block(s) are unoccupied.

two

the ABS block design is intended to prevent by keeping following trains a safe distance behind proceeding trains.

rear-end collisions

true or false: traffic directional circuits permit follow-up movements within ABS territory.

true

True or False: according to the FRA: the circuit shall be so installed that each signal governing train movements into a block will display its most restrictive aspect when the associated track relay is in the de-energized position.

True

the control circuits for home signals are controlled automatically by _ extending through the entire block.

track circuits

a signal at the entrance to a route or block that governs trains entering and using that route or block is considered a:

home signal

the battery or power supply for each signal control relay circuit must be located at:

the end of the circuit furthest from the relay.

the signal is controlled by contacts of the signals h and D relays if a signals h relay is energized and it's D is denergized it will display a:

yellow aspect

the three types of line circuits that are usually associated with ABS are the traffic circuits track repeater circuits and the _.

signal control circuits

The is the most important link in ABS system. it is the medium of connection between the train and the Wayside signal.

track circuit

True or False: Each signal head usually contains a variable resistor. The resistors are adjusted to provide voltage across the lamps, which is 10% less than the lamps voltage rating.

true

In automatic block signal system territory, the signal indications:

provide sole authority for train movements.

each track in ABS territory is divided into a series of rail segments called . The ABS system is designed to permit only one train at a time within the _.

Blocks; Block

when performing the Searchlight "rollover" or "rock" test, the most significant part of this test is:

ensure the mechanism returns to its most restrictive state

how often does the FRA require a searchlight signal to be inspected?

at least once every 6 months

A ____ is used in conjunction with a signal mechanism to detect the aspect the signal is displaying.

repeater relay

The signal is controlled by contacts of the signals H and D relays. If a signal's H relay is energized, and the D is denergized, it will display a:

yellow aspect

Each signal in ABS territory will display a number plate that designates its _ relative to the system track plan survey location.

milepost location

True or False: according to the FRA, the failure of a lamp in a light signal shall not cause the display of a less restrictive aspect than intended.

True

Should a lens of the color light signal require replacing due to damage, always replace the lens with _.

the exact same type of lens.

in the color light signal head, a _ is mounted inside that provides a means to adjust the voltage to the appropriate level.

variable resistor

The _ typically Works in conjunction with a yard switch machine and switch circuit controller and is used to convey the switch point position to train personnel.

ES-20 color light signal

routine maintenance of color light signals consists of periodic cleaning and inspections of the lenses and checking the .

voltage levels

True or False: The coded track circuit, although somewhat different from the conventional steady energy track circuits, is fundamentally the same in basic principles of operation.

True

longer track circuits, improved broken rail protection, better shunting sensitivity, and low power line circuits are all advantages of coded track except .

low power line circuits.

Electro code pulses are transmitted through the _ between signal locations, making it possible to detect trains and provide broken rail protection.

rails

Electro code transmits pulses for seconds with transmit/receive cycle lasting _ seconds.

1.4; 2.8

timing of the code pulse values are measured from the _ of the first code pulse.

leading edge

the most common use of code is for track integrity check and code _ is for block occupancy information.

code 1; code 5

the maximum number of codes that can be transmitted in one pulse using Electro code is:

4

The ____ module provides chassis and code status information in the form of LED lamps or an LED display.

216

The _ module detects current pulses from the rails with a biased transformer, an LED indicator flashes with each pulse received.

7K

The _ module produces low voltage output for the connection to the track. Adjustable taps on this module allow the transmit level to be adjusted.

2R

True or False: When troubleshooting Electro code and a track problem is suspected, it may be necessary to turn one of the electro code units off during troubleshooting.

True

to transmit a code using an electro code 4H unit, it is necessary to connect the code transmit terminal to _.

Code reference

the code normally used for a quick tumble down or traffic reversal is _.

code 6

The electro code _ unit receives codes and controls bi-directional track codes for two track circuits and light signal aspects for single or bi-directional signaling.

4

True or False: auxiliary inputs allow for information such as switch position to be used to upgrade or downgrade codes transmitted to adjacent locations.

True

the standard function of code one is

track integrity

the standard function for code to is

yellow aspect information

the standard function for codes 3, 4, and 8 is

alternate aspect information

the standard function for code 5 is

non-vital block occupancy

the standard function for code 6 is

always used as tumble down

the standard function of code 7 is

green aspect information

the 7K cards in electro code systems are

receiver cards

the 2R cards in electro code systems are the

track converter cards

the 214 card in Electro code systems is the

filter card

the 215 card in the electro Code system is the

input interface card

the 216b card in the Electoral Code system is the

test/display card

the 230 cards in the electro Code system are the

processor cards

the 212 cards in the electro Code system is the

Chopper control cards

the 213 cards in the Electro Code system are the

lamp driver cards

provides battery filtering for the modules and vital code filtering

214 filter module

interfaces with the aux inputs / outputs with the microprocessor

215 aux I/O module

monitors signals from both microprocessors and controls output to lamp converter modules

212 main Chopper control module

these microprocessor modules are redundant processors requiring agreement between the two before any vital functions are performed they contain application software on eproms

230a and 230b microprocessor modules

provide isolated lamp drive to 6 East and West lamps or four Searchlight mechanisms

213 lamp driver module

located through the top of the ec-4 cabinet and is a DC to DC converter that provides up to 60 watts to light signals

211 main lamp converter

this card prevents the electro code from shunting overlay frequency equipment operating in the same track circuit. it also provides a high impedance path for lightning strikes

9h track filter module

this module provides relay contact closure information at the end-of-siding electro code to interface relay based signal systems.

217 code select input module

this card provides up to eight relay Drive outputs to interface relay based signal systems

218 relay output module

the purpose of the electric switch lock is to prevent hand throw switches from being operated when .

main line train movements might be affected

The short audio frequency overlay track circuit used to detect train presence on the main track at the EWL location is referred to as the _.

releasing circuit/section

When the WL is energized, it actuates an internal locking key and allows the release of a lever or plunger, which enables the switch to .

unlock

The _ is an override feature used to unlock the switch should the normal EWL circuits fail (usually sealed).

emergency release

True or False: At EWL locations, typically, the WLNP (nomenclature will vary) relay is normally energized and checks the normal position of the switch points.

False

according to the FRA, an electric lock on hand operated switches Shelby controlled so that it cannot be unlocked until control circuits of signals governing movements over search switches have been _.

opened

the EWL holds the switch points in the normal position until safety checks are made.

locked

True or False: the FRA requires the electric switch lock location to be Approach or Time Locked

True

True or False: time locking prevents the unlocking of the switch until a predetermined time expires should an approach indicate occupancy.

true

approach locking ensures that if any approach is occupied the electric lock cannot unlock until .

after a predetermined time period expires.

in a traffic control system, train movements are authorized by _.

signal indication

in a traffic control system, signals at interlocking or control points are absolute signals and normally display a .

red aspect

before a signal is allowed to clear or a power operated switch to move checks are made of the to ensure a change in field conditions is safe.

vital circuits

An _ is the information sent from the interlocking conveying the events that occur at that interlocking.

indication

this type of locking ensures that once an interlocking signal has been cleared, the route it governs cannot be changed nor any conflicting or opposing signal cleared until the original cleared signal is set to stop and time has expired.

time locking

according to the FRA when an engine or car passes a proceed signal, shall be effective not more than 13 ft in advance of the signal.

route locking

the purpose of _ is to prevent the clearing of signal, or maintaining a cleared signal, if a switch contained in the route is not in the proper, locked position for the Train move.

indication locking

TCS control points in the field are connected by a number of _ appropriate to the distance between control points so that the traffic can be moved expeditiously and with safety.

automatic block signals

up to seven different types of electric locking may be possible at an interlocking (control point) location. how often does the FRA require locking test to be performed?

once every 2 years