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40 Cards in this Set
- Front
- Back
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when does the limiting resistor come in affect
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when the mcr drops. limits the current to the motor 90 to 45 degrees
adjustment of the downtime |
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When does the snubbing resistor come in affect
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90 to 10 ur snubbing the motor down
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how is the xgnpr a 3-5 sec relay
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xgnpr is a slow drop relay with a hard wire shunt across and the hell back contack of the xgnr
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what will happen if the snubb resistor is open
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90 to 45 gates come down normal
45 to 0 it will go down a little faster |
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what will happen if the snubb resistor is shorted
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90 - 45 it will go down normal
45 - 0 heavy snubbing |
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what would happen if the limiting resistor was shorted
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90 to 45 gates go down a little faster
45-0 gate will go down normal |
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how do you do a gravity down
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wch plug motor down and open gold nut
safetran same old railway plug motor down open clapper |
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what is a lock out
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directionals remain up once train clears island.
caused by exiting approach remaining out gates wont come down for a train approachin crossing in opposite direction until taps on island |
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ring through
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direction never sets gates remain down till train leaves exiting approach
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why are directional s important
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detecting the presance of the train
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where do you find LOTE
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at crossing ckt and manual block territory
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how is specific time determined
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feet per second 1.47
take 1.47 times the speed of train and divide it by the number of feet |
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in 261 what breaks directionals
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traffic
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how does this prevent lock out
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directional s stay up
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torque readings
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SAFE TRAIN 60 - 100 on horizontal
WCH 50-100 horizontal vertical 200lbs=20ft 10 lbs per each foot after |
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what does the por do?
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transfers AC to DC incase of power loss
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what are voltage reading on crossing blubs
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No less than 85% of the prescribe rating for the lamp
10v 18w 1.5a Dc adj at resistor AC lighting xfrm |
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Which do you adj first on crossing bulbs
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DC
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what would cause a gate to pump
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worn ratchet and pawl
check pick up and holding coil intermittent circuit |
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what is a COM
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Cut out repeater
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how does your flashers start
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Heel back of the XGN sending battery to the EOR
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Can you use another relay for the EOR
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FN16 add the washers to increase of decrease voltage
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what are the gate flasher measurements you should aim/ align the lights to
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front lights at 400 ft at center of road/ vertical alignment 5'6
back lights at 50 ft at center of road vertical alignment 5'6 |
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shear pins
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up to 18 ft A&b
19 to 28 B&C 29 and up abc |
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False activation
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when gates come down due to the circuitry fault instead of train NO TRAIN APPROACHING
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PARTIAL ACTIVATION
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one gate up and one gate down
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activation failure
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more then 50% of the flashers not working
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what is the min warning time before train hits island
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LIRR 30 sec
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how long should gates be in horizontal prior to train arriving at crossing
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5 sec
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main gate should have a tip light withing___ of the gate tip
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one foot
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when gates are in horizontal how high above the crown of the road should be the tip of the gate
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48 inches
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main gate should be within __ of the left edge of the approach lane
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four feet
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sidewalk gates longer than __- should have one red light
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6 ft
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what is the flashing rate
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40 to 65 fpm
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why are gate lights fused and flasher lights not ?
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in the event the gate arm is knocked off it could cause shorted wires which could cause a ground through shorted wires which could load down transformer or drain batter bus
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why are approach relays slow pick
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loss of shunt protection
to bridge the transfer time for transition |
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why are direction stick relays slow drop
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has to do with light engine. to bridge the transfer time for transition
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what are the distance of the flashers of each other on the mast
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30 inches center to center
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what is the purpose of the ckt controller
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Provides a positive check on the position of the points by opening and closing electrical circuits
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point detector
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detect if there is a deflection in the points 1/4 inch 3/8 it latches out
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