Comeng Faults from the Highlighted Courseware Flashcards
In cases of loss of traction power/critical power loss, what are the four initial things a driver must check?
Trips, switches, gauges and cocks
When checking “trips, switches, gauges and cocks”, what does the driver check in regards to the trip?
That it is set and lowered
When checking “trips, switches, gauges and cocks”, what does the driver check in regards to switches? (3)
- Switches are in normal position
- Circuit breakers are in normal position
- Doors Closed button is activated (steady blue)
When checking “trips, switches, gauges and cocks”, what does the driver check in regards to gauges? (3)
- Main res pressure is between 585 and 725 kPa
- Brake pipe is within normal tolerances (550 kPa)
- Control res air with normal tolerances (490 kPa)
When checking “trips, switches, gauges and cocks”, what does the driver check in regards to cocks? (2)
- BVICS is open (if BP is low)
- Red EC and Yellow TECHAV cocks are in normal position
Which tripped circuit breaker is most commonly the cause of a failed Comeng?
Control Circuit Breaker
What fault-finding method is undertaken if trips, switches, gauges and cocks have failed to locate the fault?
ROBBDS test (book 2 page 9, check phrasing of this question KT)
What does the ROBBDS test stand for?
Reverser
(Traction) Overload Reset
Brake Pipe Reduction
Control Governor Bypass
Door Loop Bypass
Second Controller
If an untouched train’s control circuit breaker is tripping, it is often a fault between:
The reverser to master controller cabling
How do we perform Step 3 of the ROBBDS test (Brake Pipe Reduction)?
- Make a BP reduction to below 325 kPa (Control Governor opens)
- Recharge BP pressure to above 430 (Control Governor closes)
- Try again for power
(If train gains power, the fault was likely dirt caught between Control Governor contacts)
Which reservoir supplies air pressure to operate switches within a Comeng’s main equipment case to transfer 1500v DC to the traction motors?
Control reservoir
Which three fault lights are connected to the traction system?
- Local fault light
- Line Switch fault light
- This Car light
How much air does the Control Reservoir hold?
490 kPa (+/- 20)
What effect will a faulty Control Reservoir have on a train?
It will cause switches to remain open and traction power will be unavailable on that car.
(Which switches? The courseware doesn’t specify)
In case of lack of traction due to a ruptured/isolated Control Reservoir, what happens to the Line Breakers and what fault lights/indications will a driver receive?
Line breakers will remain open. Line Switch fault will occur and no amps will be supplied to the motor car.
What should a driver do to manage a ruptured/isolated Control Reservior?
Traction Motors put to All Out and TMM submitted
How would a driver determine which pair of traction motors are defective on a motor car?
- Place Traction Cut-Out Switch to 1&2 position.
- Press Overload Reset button.
If fault lights still present, isolate 3& 4 instead and repeat.
According to courseware, what are the three major causes of loss of overhead power?
- Weak substation output or substation failure
- Overhead failure
- Defective 1500V DC circuits on Comeng trains
With loss of overhead power, the driver must stop the train and: (4)
- Check for derailment
- Contact Train Controller
- Secure the train
- Follow instructions from Train Controller to identify cause of power loss
According to courseware, 1500c DC equipment and circuits include: (5)
- Pantographs
- Associated Circuits
- Compressors
- Traction equipment
- Motor Alternators
When loss of overhead occurs, how many times will the system will automatically attempt to reset itself?
Twice
What happens to the saloon doors in a Comeng when overhead power is lost?
Doors will release
What will Metrol do if they are unable to restore overhead power?
Make a group radio call and request all drivers in affected area to lower pantographs
When lost overhead power has been restored, at what interval will Train Control instruct drivers to depart
At one minute intervals