Comeng Faults EMU test (119 of 155 from EMU quiz) Flashcards
True or false:
Isolation of the rheostatic brake to determine a cause of breaking faults can only be done on a car-by-car basis.
True
By what method can the rheo brake be isolated on the entire train?
Tripping the EP circuit breaker
If there is a fault in the train cable between the first and second cars which affects the A, B and C wires from the brake controller, what will be effect be on the train?
EP breaking will not operate on all of the trailing cars
If EP brake operates in step one and two, but fails to operate in step 3, what is the likely cause?
Failure of the B wire from the brake controller
If the EP or rheo brake is erratic in its performance, what steps must a driver take? (3)
- Trip EP circuit breaker
- Run train on Auto Air Brake
- Submit TMM
How will a second BVICS open present itself in the lead cab?
The blue Doors Open light will flash continuously
If brakes are sticking on a trailing car, what indication will a driver receive in the lead cab?
Wheelslip light may or may not illuminate
True or false:
Main res pressure will not be monitored whilst the EP circuit breaker is tripped and low pressure flag is raised.
True
What is the maximum allowed speed of a train that is running with deflated air suspension?
50% of track speed to a maximum of 30km/h
What should a driver do if the brake controller handle is moving to a more released position without driver input? (4)
- Cut out EP circuit breaker
- Run on air brake
- Isolate local rheo brake
- Submit TMM
What does a steady air con fault light indicate?
No more than one HVAC has failed on each trailing motor or trailer car
What does a flashing air con fault light indicate?
Both HVAC units have failed on one or more car
If a driver observes flashing Air Con fault light but all HVACS appear to be operating, what else can the driver check?
Air Con alarm circuit breaker above No. 3 door in all cars
A Wheelslip fault light illuminated whilst the train is in motion indicates what approximate difference of speed between the axles?
15km/h
What does an illuminated wheelslip light indicate when a train is stationary?
A fault in the wheelslip unit and its associated equipment
The control circuit on a Comeng train supplies current for which equipment? (8)
- Master controller
- Reverser
- Remote panto raise
- Remote panto lower
- Traction equipment reset
- Electric demand circuit breaker
- Speedo
- Control gov
If a train is failing to power and still not powering after testing a second master controller, what is the next step in the fault finding procedure?
Declare the train disabled
What is the correct procedure if marker lights and headlights fail during darkness and it is not possible to reverse units to eliminate the faults?
Train must be removed from service at first opportunity
If normal brake pipe pressure can’t be maintained, how could a driver ascertain the cause of the fault?
By closing the Brake Valve Isolating Cock. If brake pipe pressure remains steady the regulating valve is defective. If it falls rapidly, the brake pipe is leaking
How many turns are required to manually apply spring park brakes on a tread-brake Comeng after it has been manually released?
40-60
What must the driver of a comeng do if the brake pipe hose bursts between the centre motors and no competent employee is available?
- Close the brake pipe cocks between centre motors
- open BVICS of rear portion of the train
- run on EP brake
- Isolate VICERS in trailing centre motor
If train has failed and trip, switches, gauges and cocks have been checked, what is a driver’s next step in fault finding?
See if the train will power in reverse
How many anti-clockwise turns are required to manually release the spring park brake on a Comeng disc break train?
It cannot be manually released
What is the effect of a Lock-Out Magnet Valve being defective in the closed or energised position?
the Auto Air break will only operate in Emergency
If the compressors run continuously, after the Compressor Governor Circuit Breaker has been isolated, what is the driver’s next action?
Restore circuit breaker to normal position, then isoalte the compressor governor circuit breaker on next motor
If there was a fault somewhere on the rheo demand circuit of a Comeng, which circuit breaker would trip?
Control Circuit Breaker
Consider the following scenario on a Comeng train:
a) Master Controller is closed
b) Reverser is in FWD, neutral or reverse
c) Brake controller is in applied position
d) EP circuit breaker is set
If the control circuit breaker will not remain set, what is the likely cause of fault?
Short circuit in the rheo brake demand wire of train cable or local rheo brake controller cable on any M car
(the lack of commas make this difficult to comprehend but I copied it straight from the EMU and don’t get the concept so I can’t clarify)
(cut out local rheo and see if that’s the issue)
If Auto Air brake becomes inoperative on lead car and no competent employee is available, what must be done?
Declare the train disabled
True or false:
The rheo brake will operate normally when the EP brake is isolated
False
At 80km/h whilst in step 7 of rheo breaking, what amperage should a driver observe?
200 amps
At 80km/h, in step 7 of theo braking, at what amperage would a driver book a “low amps rheo breaking” fault?
What would a driver then need to do?
160 amps or fewer.
Driver needs to book fault and isolate rheo in lead motor
With maximum EP brake pressure in step 7, what extra braking force is provided if the handle is moved to emergency?
10%
What valve provides for the extra braking force when moving from step 7 EP breaking to Emergency?
Restricted Application Limiting Valve & Ball Check Valve
What does a raised “low pressure” flag indicate to a driver? (2)
- Pressure in main res is below a safe level (500kPa)
- EP brake is inoperative due to failure or isolation of power supply
True or false:
The LP flag will be vertical if the EP main res isolating cock has been isolated
True
If an EP fault occurs, does the “low pressure” flag continue to monitor main res pressure?
No
What is the function of the Panto Isolating Switch in the driver’s cab?
Electrically isolates the pantograph EP valve on that car, preventing it from being raised
If the local panto isolate switch is in the isolate position in the rear cab, and a driver attempts to raise all pantos remotely from the lead car, what will happen to the rear cab panto?
It won’t raise, as panto raise motor has been isoalted
If 1500v overhead supply is weak, Metrol may instruct drivers in affected area to leave how many MAs operating?
One
When the rheo brake isolating switch in the driver’s cab has been placed to isolate, what will be the effect on the train?
Isolates rheo brake in that motor car only
The Aux isolating switch in the driver’s cab performs what function?
Isoaltes Aux EP valve on that motor car only
If Aux Isolating Switch in trailing cab was in Isolate position, and a driver pressed Aux Start in leading cab, what would occur?
MA on trailing motor would not start as MA start valve has been electrically isolated
The LSM performs which functions when the train is running? (4)
- Detect reduction of DC voltage
- Stop remote MAs
- Lower remote pantos if train under 8km/h
- Trips EP circuit breaker to run air brake if total loss of power
If a comeng is stationary with pantos raised, what functions does the LSM provide?
- Detect reduction of DC voltage
- Stop ALL MAs
- Lower remote pantos
- Trips out EP circuit breaker if total loss of power
When preparing train for service and pantos will not remain raised, what can a driver isolate to ascertain if that equipment is causing the fault?
LSM power switch
When preparing train for service and MAs will not start, what can a driver isolate to ascertain if that equipment is causing the fault?
LSM power switch
When preparing a comeng for service and the EP circuit breaker trips continuously, what can a driver isolate to ascertain if that equipment is causing the fault?
LSM power switch