HCMT Pneumatics Flashcards
Where is compressed air supplied on the HCMT?
- Main reservoirs.
- Pantos
- Air suspension systems.
- Electro pneumatic braking systems.
- Trips.
- Sanding equipment.
- Couplers.
- Horns
- Driver and O.J. T seats
What is the operating pressure for the main Reservoir?
850 to 1000 KPA
Table of pressures
What is emergency brake cylinder pressure
280 to 460 K PA
What is maximum brake cylinder pressure?
250 to 380 K PA
Holding brake cylinder pressure is
140 to 240 KPa
What is the Main reservoir overpressure safety valve set at?
1050 K PA
What is the main reservoir safety loop activation pressure
600 KPA
What does the air supply unit consist of?
(ASU eq. Case)
Main air Compressor
Air dryers
Filters
Where is the air supply unit located?
ASU
under frame of TC (B side)
How many compresses are inside the air supply unit equipment case and What is their purpose?
Two
They maintain main res, operating pressure
How do the compressors in the ASU equipment case operate in order to reduce wear?
They alternate days of operation as the primary compressor
When will the secondary compressor operate?
When the TMS identifies that the primary compressor is unable to maintain main res pressure
During start up when main res has not yet reached operating pressure
Where are the auxiliary compressors located?
Only on the DMP cars
When will the auxiliary compressor automatically raise the Pantos?
When there is insufficient main res. pressure on train start up
When the car has been isolated from the main res system
What will happen if the main res supply is isolated from the Pantos on a DMp car? will that stop the Pantos from raising?
No
This is because the auxiliary reservoir will continue to supply compressed air to the Pantos
Which reservoirs does the main res system charge and supply compressed air to?
The main reservoirs,
the surge reservoirs,
the brake supply reservoirs
Which system controls main res. pressure in operation?
The TMS system controls and regulates, main res. pressure
How is Main res. pressure isolated
If the MR through Cock on a car isolated, the cock on the adjacent car must also be Isolated
What is the main res pressure safety valve purpose?
To protect the MR from overcharging
How many surge reservoirs on each car and what do they do?
4
They supply Compressed air to the airbags for air suspension
How is the brake supply reservoir charged and what is the function?
Charged via the brake control module. Its function is to supply compressed air to the EP valves in the BCM to charge the brake cylinders.
How is the trip reset? (2 methods)
Via trip reset switch on OJT panel (and reset EMY brake as well)
Or
Press the Reset plunger on front of trip
When isolating the trip what else must be isolated?
The trip bypass switch
in the drivers cab which Will introduced the Safety system bypass acknowledgement button
Driver must also test the trip to ensure its not functioning and manually raise it
What is the post trip speed restriction and when does it activate?
It activates once the trip has been activated.
It restricts the speed of the train by cutting traction power above 25km/ h
(However train may roll on a down hill)
What are some examples of post trip speed restriction assisting drivers comply with sections of the 1994 book of rules
Passing an Auto signal at stop (R1S3)
Trip valve irregularly operated (R9d S5)
When operating under Extreme caution
How long does the ‘post trip speed restriction’ apply for ? **
500 seconds from the time the train commences moving after a trip activation, unless cancelled by the driver.
How is The trip speed restriction canceled by the driver?
By pressing the TRIP SPEED button
What is the purpose of isolating, the horn ?
It isolates the flow of MR air to the horns, which means there will be no sound from the Horn
When do we use the uncouple device isolating cock?
Only if we rescue another train
What is the function of the uncouple isolating cock?**
To restrict the flow of MR to the uncouple device.
If this is isolated, remote, uncoupling from the drivers cab will not be available
Where are the driver and OJ isolating Cocks located?
Beneath the seats, if isolated, this will restrict the flow of MR air into the seat. The seat will lower, but the controls and suspension will not function
When does the sanding equipment usually function?
Only in normal operation and only during braking. It is also available during traction in recovery modes
When isolated on which cars does the sanding equipment not function?
Only on the car that is isolated on
What is the function of a tread scrubber?
A tread scrubbers purpose is to clean debris from the Wheel Face to ensure proper conductivity of the track circuit
On which cars does EP break operate on?
On all cars
On which cars does the holding brake apply?
On all cars
On which cars does the emergency brake apply?
On all cars
On which cars do the park brakes apply?
On all cars except for the TC cars
On which cars does the ED braking system apply
Only on the motor cars so the DMP and the MP cars
What is the purpose of the BCU?
It’s a computer that controls the application and release of EP friction braking
it, receives brake demand and commands EP valves within the BCM to channel air into the brake cylinders
What is inside The variable voltage variable frequency unit
The traction control unit, and two traction inverters
What happens in the event of an emergency brake application or wheel slip?
The TCU will suppress any ED braking demand, and the BCU will take over all of the braking
How does EP friction braking work on HCMT?
1.,Main Res. air is channeled via the BCM to the brake supply reservoir
2. When an EP brake demand is received the BCU commands EP valves to channel air from the brake supply res. back through the BCM and into the brake cylinders
Which isolating, Cocks isolate, EP friction brakes
Saloon, brake supply I.C. (1 per car under a seat in cabinet B06)
The brake cylinder isolating cox bogies 1 & 2 in the brake control module
The brake supply, isolating, cock in the BCU
one in each car
(Isolates EP friction brakes in that car only)
What will happen if the EP friction brakes are isolated on the TC cars?
The train must be declared disabled
What must happen if the EP fiction brakes are isolated on a car that is fitted with Park brakes?
The park brakes must also be isolated and manually released
What must happen if three or more bogies are isolated on a seven, HCMT? ***
The train will be removed from service
What is the brake manager and what happens if it is active or inactive?
The brake manager is the BCU that controls brake management in an active cab…it directs all the BCU’s on the train.
The brake manager is active during EP braking with up to two bogies isolated. - The train will request extra braking effort across all remaining bogies to compensate so the stopping distance should be similar to normal EP braking
When the brake manager is inactive during EP braking with up to two bogies isolated, Each car is braking independently with no additional effort for compensating… stopping distance is close to normal EP braking (within 10% of normal service brake requirements)
Which equipment controls ED braking force?
The TCU according to brake demand received from the master controller
From what speed is ED braking available?
Above 3 km/h
How is the ED brake isolated
It is self isolating. If there is a fault in the system, the train will still stop using EPfriction braking.
The TMS will automatically attempt to reset it once the master controller has been moved to the coast position
What is Service braking?
Braking modes, used to slow and stop the train in normal operation
What kind of service brakes Are used on the TC and the Centre trailer?
EP friction brakes only
Which equipment calculate brake blending?
BCU
What does the BCU measure to determine the required braking force?
The ED braking force present.
The braking force requested by the driver.
The loading of the car
What speed threshold does the holding brake apply automatically?
0.5 km/h
When will the holding brake release?
When The safety loop is energised
When Brake demand is not registered
Traction demand is registered above the defined traction threshold, which is 50%
When is the emergency braking system activated?
MC handle is in EMY
ESB is pressed
Hand and foot pilot valves are not set for a certain time when moving
when H/Foot not set & the MC has less than a 50% brake application when stationary
Trip cock activated
Vigilance penalty application
MR below 600
TU demand for EMY brake
Safety system bypass reminder time out (when on secondary circuit)
Physical interruption of the safety loop, (such as train, being separated, for example)
METH PMS TV
When can the safety loop be reset?
When the train stationary for more than three seconds
The reason for the emergency brake application is reset
MC to max brake,, reverser to neutral
Which tasks are linked to the vigilance system and can be used to reset the vigilance cycle?
• VICERS button
• Movement of the MC (5% change in demand in 3 sec window)
• Activating the horn
• Headlight wiper washer switch
• Safety system bypass acknowledge
For the master controller to trigger the task link reset of the VICERS, How much of a change in demand for power/ braking should there be?
There needs to be a 5% change in the power or brake demand within a 3 sec window
When do the ED and EP friction brakes blend?
- When the BCU detects a need for both EP and ED during wheel slip or rapid full brake application
- When the speed of the train is between 10 and 3 km/h and EP is required to compensate
When do the park brakes apply? *
Automatically when the driver turns the MC switch to off, and it automatically releases when the holding brakes are released
How are the park brakes isolated?
To isolate the park brake, the driver must do the following in this order
- Pneumatically isolate the park brakes
- Manually release the park brakes
Where are 2 park Brake isolation cocks
There is one located in Cabinet B07 near door 3
The BCM park brake isolating cock (all cars except TC)
- You can isolate one or the other
To manually release the park brakes how many park brake manual release devices must be operated for each axle?
1
(EP BRAKING WSP)
What are the speed sensors on each wheel for?
Each axle is fitted with a speed sensor for the BCU, which monitors the axles for differences in speed. If there is a difference in speed between axles, the BCU will activate the dump valves to the associated brake cylinders venting brake cyl. pressure until it confirms the affected axle accelerates.
Driver will get a TMS notification
(ED BRAKING WSP)
What happens in relation to the TCU & BCU if there is wheel slide during ED braking?
The BCU will command the TCU to cut off the ED breaking force when it detects a difference in speed of the axles. Braking force will be supplemented with EP fiction braking
Driver will get a TMS alert
What happens with the TRACTION SYSTEM (WSP) if the speed or acceleration of one axle is significantly higher than the others?
The traction system cuts these motors off.
Driver will get a TMS alert
What does the primary suspension consist of?
Rubber laminated Springs mounted between the axle box and the bogie frame
What does a secondary suspension consist of?
Airbags for shock, absorption, and dampers
*these are mounted between the bogie frame and the car body
What are the leveling valves and what’s the function?
Mounted in between the bogie frame & car body.
They read and maintain the car body height at a constant level for alignment with platforms, and infrastructure in conjunction with the airbags.
How do we isolate the secondary suspension i.e. air suspension? *
Both Air suspension cocks on that car must be isolated. A single bogey cannot be isolated independently.
