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
If a train fails and the driver is unable to contact train control, can it be assumed a loss of overhead has occured?
No way. Gotta do fault finding first. Check those Trips, Switches, Gauges and Cocks etc.
What items can a driver check to confirm presence of 110v DC? (3)
- Bell
- EP operational
- Low Pressure flag is lowered
What items can a driver check to confirm presence of AC power items?
- Saloon lights (non-emergency)
- Van area cab light
- Operation of headlights
If a driver’s overhead is restored during fault finding, they must return to lead cab and raise pantos/start MAs. If they have no communication, how long must a driver wait before applying traction power? How far can they power?
- 30 seconds for UP
- 60 seconds for DOWN
Must remain in SERIES until next platform
If there is suspicion of disarranged overhead, what two personal safety measures must a driver take?
- Must remain in cab
- Must make PA asking passengers to remain on train
When loss of overhead occurs, how long will emergency lights run for?
Two hours
Loss of overhead:
How can a driver reset the emergency lights?
Toggle marker lights from auto to any other position and back
Loss of overhead:
How is a driver informed of the need to reset the emergency lights
Battery charger light will flash on driver’s fault panel
Loss of overhead:
How long will PA system be available for? How can it be reset?
Up to two hours. Reset when emergency lighting is reset
What is the purpose of the LSM (Loss of Overhead Shutdown Module)? How does it work?
To reduce the impact of 1500v DC defects from overloading the substation when lost overhead is returned. It works by switching off certain circuits when overhead is returned
What is the LSM speed threshold?
8km/h
Train moving OVER 8km/h and BVICS OPEN in lead cab:
If overhead power is lost and the 110vDC output drops to 95v DC for 2 continuous seconds, the LSM will activate and: (4)
- Trip the Ep circuit breaker (low pressure flag raises)
- Leave local motor alternator contactor set to on
- Shut down motor alternator
- Train can only be driven on air brakes
Rheostatic breaking deficiencies can only be diagnosed at what speeds?
Speeds above 8km/h
Train moving OVER 8km/h and BVICS CLOSED in trailing cab:
If the LSM is activated it will have what effect on the MA contractors? (2)
- Set the MA contactors to OFF in trailing cabs
- MAs will shut down due to loss of overhead supply in trailing cabs
Train STATIONARY and BVICS CLOSED in trailing cab:
If the LSM is activated it will: (4)
- Drop all trailing pantos
- Lead panto will be raised
- Leading MA contactor will be ON
- Trailing MA contactors will be OFF
(straight outta courseware)
Control Circuit Breaker Tripping – Master Controller Closed
The control circuit breaker may trip due to a defect in which 5 pieces of equipment on any motor car in the consist?
- Master controller
- Train cable
- Reverser equipment
- Traction power control equipment
- Rheo brake demand circuit
What are the THREE probable causes for the Control Circuit Breaker tripping in the following circumstance:
- Master controller closed
- Reverser in FWD, neutral, or REV
- Brake controller applied
- EP circuit breaker set
- Rheo brake isolate switch in normal
- Short circuit on the electric brake demand wire in the train cable
- Fault in the rheo brake control equipment on any motor car
- (not highlighted in courseware) Short circuit between control circuit breaker and master controller
How is the train cable connected between two centre motors?
Through spring-loaded contacts in the Scharfenberg coupler
What will a driver observe if the Control Circuit Breaker trips when operating the Remote Panto Up or Remote Panto Down buttons (2)
Remote Panto Up: Pantos cannot be remotely raised
Remote Panto Down: Pantos cannot be remotely lowered
What will a driver observe if the Control Circuit Breaker trips when operating the Overload Reset?
Driver will observe that overloads cannot be reset
What will a driver observe if the Control Circuit Breaker trips when operating the Master Controller?
Driver will observe that they cannot get traction power in one or all powering positions
What will a driver observe if the Control Circuit Breaker trips when operating the rheo brake?
Driver will observe a failure of the rheo brake
How many running Motor Alternators are required to provide the train with a 110v DC supply?
One (though it will be in a degraded mode)
What will the effect on a three-car unit if one motor alternator stops working? (4)
- Saloon lighting at 50% capacity
- Air con at 50% capacity
- Cab lighting and heating at 50%
- Local rheo where MA has failed will be inoperative
How long after loss of overhead until the VICERS Activation Valve will open, causing brake pipe to exhaust to atmosphere?
5 minutes
If lost overhead is likely to be caused by a defective train, how will Metrol ascertain which train contains the defect?
One by one, Metrol will request a train raises all pantos and starts all motor alternators. When overhead is lost again, it will indicate the defective train.
At what pressure does the safety valve open on a Comeng?
775 kPa
What are the two pressure settings on the compressor governor?
HIGH (725 kPa)
LOW (585 kPa)
Fill the blank:
If brake pipe pressure cannot be maintained above ____ kPa, declare the train disabled and make arrangements for relief
425 kPa
Are the compressors able to run continuously if required?
Yes
How can a driver ascertain which faulty compressor governor is causing the compressors to run continuously?
((what extra thing should they check?))
Electrically cut-out each compressor governor in turn until the compressors stop operating.
(Compressor must be cut back in before moving to next compressor)
((Also, check iso cock is not turned))
How can a driver manage a faulty compressor governor which is causing the compressors to run continuously, if the train is in running or if there is no time to fault find at the terminal station?
Driver should isolate compressor governor in lead motor and continue driving.
What two indications might a driver get from a minor leak within the main res air system? (2)
- MR air pressure falling
- Air compressors running continuously
What are the main res air systems on a Comeng? (10)
SWAMP BED CC
- Spring park brake system
- Whistle
- Air suspension
- MA contactors
- Pantographs
- Brake pipe charging
- EP braking system
- Door system
- Compressor governor
- Control res system
What eight things can cause a FDCL if the doors are closed?
- Control Circuit Braker tripped in a rear cab
- Rear motor tail lights turned off
- Auxillary Circuit Breaker tripped in another cab
- PLC circuit breaker tripping in any trailing car
- Door System Faults
- Open circuit in the Train Cable
- The train not registering a decoupling having taken place
- Second BIVCS open
What lights on the fault panel are likely to illuminate in the case of saloon light defects? (3)
MA
AC
“this car” (if applicable)
What should a driver do if unable to turn saloon lights on from lead motor?
Try turning them on from other motor
How can a driver attempt to turn on saloon lights from the lead motor if they are inoperative throughout the whole train?
Press the “saloon light” button 3 times and then hold for 3 seconds
What is indicated to a driver if saloon lighting is defective in a regular pattern?
A lighting circuit breaker has tripped
What is indicated to a driver if saloon lighting is defective in an iregular pattern?
It is caused by an operative tube
If all saloon lights are defective in one or more cars, and emergency lights are inoperative, the train must not operate: (3)
- During hours of darkness
- Through the MURL
- Through West Richmond tunnel
Train Rescue, Comeng pushing a disabled Comeng.
After attaching, the driver of the assisting train will: (9)
- Remain in the attached cab
- Ensure train-line park brakes are applied
- Isolate VICERS key switch
- Isoalte the Door Loop Bypass key switch
- Raise the trip
- Apply and isolate the auto air brake
- Turn the Red EC cock
- Set the foot pilot valve
- Press the Control Gov Bypass button
Train Rescue, Comeng pushing a disabled Comeng.
How do the drivers conduct a continuity test?
Front cab puts brake handle to Emergency
Centre cab confirms that BP has reduced
True or false:
If the LSM trips, the main things that full function on a train are the emergency saloon lighting and PA system.
True
What happens to the contactors in the lead cab if train is stationary, the BVICS is open in lead cab, and LSM activates?
Lead contactor stays on, rest of contactors turn off
What pieces of equipment are attached to the Control Circuit Breaker? (7)
MR TESC P
- Master controller
- Reverser
- Traction Overlead Reset
- Electric demand something
- Speedo
- Control governor
- Pantos up/down
What brake is available in case of main res rupture?
Emergency brake only
If pantos don’t raise remotely from the lead motor, how can a driver raise them?
Locally from each motor
How does a driver manage a main res rupture in a non-lead cab? (5)
- Isolate the panto on affected motor
- isolate Main Res (removing EP, rheo and spring park brakes on that car)
- manually release SPB
- Turn motors to “all out”
- Turn off compressor governor
What is the maximum speed a driver can perform if brake pipe continuity is affecting the train?
15km/h
If up to 2 bogies are isolated on a train, what speed restrictions apply to that train?
Above 60km: drop 10km from track speed
Below 60km: track speed
What is the maximum speed a train may go if the lockout magnet valve is defective in closed/energised position?
15km/h
How might a driver identify a charging valve or regulating valve fault in a Comeng?
Charge brake pipe and close BVICS. If brake pipe pressure leaks off rapidly, it’s likely a brake pipe rupture/defect. If it charges again to below full (with BVICS re-opened) it is likely a charging/regulating valve defect.
What circuit breaker is likely responsible for a whole-side-of-train door fault?
Auxiliary control circuit breaker
What item is faulty if all three brakes are able to be utilised at once?
Restricted application valve
How can a driver identify sticky breaks?
Feel of train, smoke, smell, retardation, observation of fault lights/brake cylinder gauges (if on bogie 1 of lead motor)
How can a driver rectify sticky brakes in running?
Switch to air brake, make one full application of air, then release.
How can a driver rectify sticky brakes whilst stationary?
Fan rheo brake a few times. Power and shut off, observe if train rolls
What does the control res supply?
Trip and line breakers
What equipment is attached to the traction overload reset button? (4)
- MA
- Line breakers
- rheo brake
- traction motors
What is the purpose of dump valves?
To prevent sticky brakes
Can a comeng be run in revenue with both bogies isolated on a lead or trailing motor?
No
Skidding wheels can be caused by: (3)
- Heavy brake applications, especially in wet or frosty conditions
- Sticking brakes
- Mechanical failures (seized axels or traction motors)
How is a train able to be driven if the lead wheels of the lead motor become locked or jammed?
Train must not be driven forwards – must return to the station in the rear
What are the two indicator marks on composition brake blocks, and what action is required when wear reaches each mark?
25mm – if wear has entered this zone, no action is required
10mm – if wear has entered this zone, block is serviceable but must be reported as worn
At what level of wear does a brake block become unservicable?
When the block head is exposed
What action is required if between 12.5% and 50% of a brake block breaks off and what category fault is it?
Submit TMM and continue driving – maintenance fault
What action is required if over 50% of a brake block breaks off on one bogie only, and what category fault is it?
Isolate bogie and submit TMM – serious end run fault
What action is required if over 50% of a brake block breaks off on more than one bogie, and what category fault is it?
Isolate bogies and submit TMM – critical fault
What are the Westcode brake cylinder piston settings in the applied position?
30mm to 65mm long
How many bogies on a six-car train can be isolated for 90% to be considered operational?
1 bogie
How many bogies on a six-car train can be isolated for 80% to be considered operational?
Two bogies
(one bogie for a three-car)
What is the purpose of the Door Loop Bypass?
To allow a train to gain traction power when experiencing a FDCL
Can a driver take passengers if the Door Loop Bypass has been activated?
No
If one saloon door is defective, is the fault likely mechanical, pneumatic or electric?
Mechanical
What should a driver do if one saloon door is mechanically defective?
Close door and use a Temporary Door Locking Device to achieve a steady blue door closed light.
If one side of saloon doors is defective, is the fault likely mechanical, pneumatic or electric?
How does a driver address this?
Electrical or pneumatic (more likely electrical)
Driver must check door switches and circuit breakers inside electrical cabinet above Saloon Door 3. If issue is not electrical, check pneumatic isolating cocks
If a whole car’s saloon doors are defective, is the fault likely mechanical, pneumatic or electric?
How does a driver address this?
Most likely pneumatic.
Driver should check pneumatic cocks. If fault does not prove to be pneumatic, driver should check electrical systems
If saloon doors on entire train are defective, what is the likely cause of fault?
Likely an issue with the Auxiliary Control Circuit Breaker.
What will happen if a driver is unable to free a jammed charging valve?
What brakes will be available to the driver?
What speed may the train operate at?
- competent worker must attend
- worker must use BVICS to charge brake pipe on trailing car, and close BVICS when done
- lead driver can drive/brake form leading cab, but will only have emergency brakes available
- maximum speed 15km/h
If no competent worker, train must be declared disabled
What is the result if the lock-out magnet valve is defective in the closed/energised position?
No Air Brake available
What is the result if the lock-out magnet valve is defective in the open/de-energised position?
Simultaneous application of the air brake AND rheo/ep brakes
What should a driver do if the lock-out magnet valve is defective in the open/de-energised position?
Trip the EP circuit breaker and run the train on the air brake
What pieces of equipment control the operation of the Emergency Application Valve?
Hand and foot pilot valves
What six things occur when the Emergency Application Valve fails to reset?
- Emergency brakes apply
- Control governor opens and will not close
- No control voltage to master controller
- brake pipe cannot be recharged
- auto air brake can’t be released
- train will not power
What must a driver do if the Emergency Application Valve fails to reset?
Turn the Red EC cock and drive on the secondary circuit
When driving on the secondary circuit, if the Secondary Emergency Application Valve won’t set, what must a driver do?
Declare the train disabled
What does the Release Prevention Valve do?
Prevents the auto air brake from releasing when the brake controller is in any other position than release
What braking system should the driver use in the case of a defective release prevention valve?
EP/rheo brakes
What is the function of the regulating valve?
Controls pressure output of the brake controller into the brake pipe, in all positions of the auto air brake except emergency (essentially, maintains brake pipe pressure)
What are the output pressures of the regulating valve in the release and full-service positions?
Release = 550 kPa
Full-service = 380 to 410 kPa
What should a driver do if brake pipe pressure only charges to between 425 kPa and 550 kPa?
Run train as normal, monitor, and book a TMM
What should a driver do if brake pipe is only charging to a pressure below 425 kPa?
Declare train disabled, though train can be moved out of section with competent employee
How should a driver operate if a fault is causing the brake controller handle to move independently towards a more released position?
Drive on the air brake – release prevention valve will ensure braking effort is maintained
What is the first thing a driver should check for when there is sudden loss of brake pipe pressure?
Derailment
What is the first thing a driver should do (besides check for derailment) when there is sudden loss of brake pipe pressure?
Place the brake controller into Emergency (if brake pipe charges as normal, cause is likely backtripping and not rupture)
How can the driver reset the trip, in case of backtripping? (2)
Place brake handle into Emergency.
Return handle to run and release
How does a driver reset the VICERS in the lead cab?
- Train must be stationary
- Master controller to coast
- Brake controller to emergency (brake pipe below 25 kPa)
- Wait 10 seconds
- Press VICERS button
- Return brake handle to run and release
What must a driver do in case of a faulty VAV (VICERS Activation Valve)?
Drive on secondary circuit
What rules must be applied when removing a train with a defective brake pipe from the section? (6)
- Train must be driven/braked from portion of train with longest continuous brake pipe
- Minimum 50% continuous brake pipe is available
- Competent Worker is available (either apply SPBs on unbraked lead/trail car OR observe and communicate if train driven from trailing unit)
- Max speed 15km/h
- Passengers detrained
- Shunt to first available siding
What must a driver do if there is a ruptured brake pipe on cars 1, 2 or 3 of a six-car set, and no competent worker is available?
Declare the train disabled
What must a driver do if there is a ruptured brake pipe on cars 1, 2 or 3 of a six-car set? (competent employee is in attendance) (4)
Driver must:
- Release air brake on defective car using hand release valve
- Trip EP circuit breaker on train to be driven from
- Instruct competent employee to ride in lead motor and give necessary feedback
- Drive from most convenient motor not exceeding 15km/h
What additional steps must be taken if there is a brake pipe rupture on cars 4 or 5 of a six-car set, and there is no competent employee? (2)
What is maximum speed a train can be driven this way?
- Isolate the Main Res to 7-Step Relay cock
- Open BVICS on trailing motor (this allows EP brake to operate in trailing car, but isolates it from defective car)
Maximum speed 15km/h
What should a driver do if there is a brake pipe leak between the Brake Pipe to Triple Valve isolating cock on the Brake Unit?
(Brake pipe defect does not affect brake pipe continuity)
- Isolate the rupture
- Release brakes on defective car with hand release valve
- Isolate Main Res to 7 Step Relay to prevent EP from operating on that car
How many amps should the rheo brake be drawing during normal operation?
100 to 250 amps
If rheo brake is feeling ineffective, how can it be isolated along the whole train?
With the EP circuit breaker/operating on air brake
If rheo brake is isolated, cars will run using EP brake. If brake performance under these circumstances is deficient, possible reasons are: (4)
- Interruption of the electrical wiring within the train cable, which serves the 7 step relays
- Defective brake unit on individual car
- Defective brake controller or relay unit
- Mechanical breakdown of the brake rigging on individual car
What happens when the driver applies EP brakes when there is a defect in the train cable behind the first motor?
EP brake will only be activated on the first car – none of the other cars will have EP Brakes
If the BVICS is closed, what is the only position of the brake controller that will be operative?
Emergency
What happens to a train if the air brake is inoperative on a lead or trailing motor?
Train is declared disabled
(competent employee may help apply park brake in emergency)
If there is a main res defect, what brakes are available to the driver?
Emergency only
How does a driver manage a train with defective main res, without a competent employee?
Declare train disabled
What is the maximum speed a driver can operate at with a main res defect, if there is a competent employee?
15km/h
What must a driver do in case of Main Res pipe rupture under any non-lead motor? (7)
- Turn Main Res cocks at both ends of the motor car
- Manually release SPBs on that car
- Lower local panto on affected car, electrically isolate it with toggle
- Isolate local panto pneumatically
- Motors to All-Out
- Remove passengers from affected car and move to other car (passenger doors should be made inoperative, Door Loop Bypass activated in driving cab)
- Isolate yellow TECHAV cock to prevent trip activating
What are speed restrictions/passenger restrictions if Main Res pipe has ruptured under a trailer car?
Train driven in accordance with deflated air – 50% of track speed to maximum of 30km/h)
Passengers must be detrained at next platform
What must a driver do if there is a ruptured Main Res tank on a motor car? (3)
- Close MR delivery cocks
- Place Compressor Governor contactor switch to OFF
- Isolate the Compressor Governor circuit breaker
What should a driver do if the leakage in Main Res air is caused by a flexible hose bursting between cars? (2)
- Close the MR cocks on both sides of affected hose
- Submit TMM
What is the speed restriction in place in case of deflated or defective air suspension?
50% of track speed to a maximum of 30km/h
Where does the control res receive its air from and how is its pressure determined?
Receives air from main res, pressure is reduced to 490 kPa via a pressure reducer
What will happen if any pneumatic rupture is ignored?
The train will eventually deplete its main res and will need to be declared disabled
What should a driver do if there is a leak in the pipe between the Main Res and the Control Res IN? (3)
- Isolate Control Res In cock
- Pipe must be blanked if broken on Main Res side of Control Res In cock
- Place motors to All-Out and submit TMM
What should a driver do if there is Control Res air leaking from the Trip Latch Lever? (1)
- Isolate the Trip Gear cock in the van cabinet
Why does placing the reverser to FWD, neutral or REV help identify if an electrical fault is in the rheo brake?
When reverser is set to FWD, neutral or REV, no power flows to reversing equipment until placed into powering.
Provided the brake is in an applied position, rheo brake demand will be sent via the train cable to the rheo control equipment in every car.
If a circuit automatically trips when the reverser is placed to FWD, neutral or REV, it is likely an issue with the rheo brake
How can a faulty rheo brake be identified/rectified if it causes a short circuit in the control circuit breaker? (2)
- Set local Rheo switch to Isolate
- Attempt to reset control circuit breaker
If reset does not hold, trip out entire rheo brake with EP circuit breaker
If control circuit breaker resets, continue to drive on air. If not, continue fault finding.
In Step 4 of the ROBBDS (Control Governor Bypass), what do we need to isolate for fault finding purposes and how do we do it?
We isolate our TECHAV equipment, by turning the Red EC cock and setting the Emergency Control Governor.
Go to next step if power not obtained.
In Step 5 of the ROBBDS test (Door Loop Bypass), what are we testing for and how do we test it?
Testing for a fault in the tractional inhibit function of the FDCL system.
We test by isolating the door loop bypass button and trying again for power.
If power is obtained, fault is in the traction inhibit system and passengers must be detrained.
In Step 6 of the ROBBDS test (Second Master Controller), what are we testing for and how do we test it?
We are testing a master controller in a different cab to see if it will power without setting the control circuit breaker.
We do this by (obviously) cutting into a non-lead cab and seeing if we can power the train from there.
If train powers, competent employee is needed to help train clear section.
If train doesn’t power, train is considered disabled
How do we perform Step 2 (Overload Reset Button), and what are we testing for?
We are to see if a traction overload is causing the control circuit breaker to trip.
We do this by pressing the traction overload button and trying again for power.
If train powers, submit TMM.
If train fails to power, continue to Step 3.
