Pneumatics Flashcards

1
Q

What equipment runs on compressed air? (7)

A

Main Reservoirs
Auxiliary Reservoirs
Air Suspension Reservoirs
Surge Reservoirs
Whistle
Friction brakes
Spring Park brake

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2
Q

What pressure does the Compressor Governor / Compressor Pressure Switch maintain the Main Reservoir at?

A

850 - 1000 kPa

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3
Q

What pressure are the Safety Valves set at?

A

1100 kPa - between compressor and air dryers

1050 kPa - between air dryers and Main Res.

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4
Q

What happens if the Compressor Pressure Switch (CG) is isolated?

A

The air compressor will run continuously

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5
Q

What is the air suspension system made up of? (3)

A

Levelling valves

Air bags

Surge reservoirs

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6
Q

What do the Levelling Valves do?

A

They Inflate or deflate air bags according to passenger load

On DM Cars: One on each bogie.

On T Cars: Two on No.1 Bogie, 1 on No.2 Bogie

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7
Q

What happens if air bags fail?

A

There is a spring system as well.

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8
Q

What do the Surge Reservoirs do?

A

Supply air to the air bags to compensate for:

Train tilting around corners
Uneven passenger load
Sudden imbalance in suspension system

Two surge res. per bogie

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9
Q

What is the Brake System comprised of?

A

Service Brake (Friction
Holding Brake
Emergency Brake
Park Brake

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10
Q

What is the Service Brake made up of?

A

ED

EP

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11
Q

When does the ED Brake work?

A

Normally, above 10kmh

Between 5-10kmh. brake blending occurs

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12
Q

What happens during wheel slide?

A

ED brake drops out and EP brake takes over

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13
Q

What is the EP brake used for?

A

Stopping at low speeds when ED brake fades out

Assisting ED brake during heavy high-speed braking

Supplementing braking demand when effort provided by the ED system is insufficient

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14
Q

What happens if ED brake fails?

A

EP brake will automatically take over

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15
Q

What kind of brakes are on TCars?

A

EP brakes only

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16
Q

When does the Holding Brake apply?

A

when MCH is in 0 (coast) when train is stationary.

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17
Q

What is Holding Brake pressure?

A

110 kPa (+/- 30 kPa)

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18
Q

When does Holding Brake pressure release?

A

When traction power is applied

19
Q

What happens if train is stationary and and a different braking position is selected (B1-B6)

A

The corresponding braking pressure will be applied

20
Q

What is B6 (Full Service) pressure?

A

189 kPa

21
Q

What is Emergency pressure?

A

280 kPa (+/- 30kPa)

22
Q

What is Main Res operating pressure?

A

850-100 kPa

23
Q

What happens if MCH is moved to B1, B2 or B3 when the train is on a gradient?

A

B1-B3 pressure are below Holding pressure so the train may roll

24
Q

What must you do with BCH when moving between braking and powering?

A

Remain at ZERO/COAST for 1 second to allow TCU/BCU time to set up

25
Q

What fault lights come up when Service Brake is applied?

A

Maintenance Fault Light
General Fault Light

They will flash and should not be considered a train fault

26
Q

What brakes are used during emergency braking?

A

Friction brakes only

26
Q

When do SPBs apply?

A

Automatically when Master Key is turned to OFF

Automatically applies when Main Res. pressure falls below 350 kPa

Park Brake Switch in drivers cab illuminates if one SPB is applied

27
Q

Where are SPBs located?

A

Wheels 3 and 7 on every car

28
Q

Can SPBs be manually released?

A

Yes

Manual release device located on each side of every bogie

29
Q

Which SPB is locked?

A

Number 1 Bogie

30
Q

What happens if the SPB is applied with the train speed over 5kmh?

A

Safety Loop will de-energise and emergency brakes will apply

Reset Safety Loop by placing MCH into ZERO

31
Q

What is procedure to manually release SPB?

A

Isolate the Bogie

Pull the handle to release SPB

Reinstate Bogie

32
Q

How does the Brake System work?

A

MCH sends electrical signal to BCU which then processes input and applies/releases brakes through the Brake Module on each bogie accordingly

33
Q

What does the braking system consist of? (5)

A

BCU (one per car)

Brake modules (two per car)

Brake Cylinders (every wheel)

Parking Brake Cylinders (Wheels 3 and 7)

Associated ICs

34
Q

What does the BCU do?

A

It’s an electronic microprocessor that receives and interprets signals from various sources to determine ED/EP braking requirements

35
Q

How are BCUs on DM different to those on TCars?

A

DM BCUs operate in conjunction with TCU

On trailer cars, there is no ED braking and no TCU

36
Q

What information does the BCU use to work out braking requirements? (4)

A

Load/weight (from secondary suspension)

Speed (from pulse generators on each axle)

ED brake information (from TCU on a DM car)

Wheel slip protection

37
Q

Which isolating cocks do we need to know in the Brake Modules ?

A

Top - air suspension

Bottom - bogies

38
Q

How does the TCU manage wheel slip?

A

When ED braking effort falls below 90% TCU drops ED and EP takes over

Sanders automatically dispense

39
Q

How do you reset EP to ED during wheel slip?

A

If safe, move MCH to 0 or a powering position for one second then return to desired braking position

40
Q

What is each sand box equipped with?

A

Padlock

RED LED illuminates if sand is below 20%

White manual test button

Sight glass to see dryness of sand

41
Q

When do sanders operate?

A

Only during EP braking

Not powering or ED

42
Q

What speed do sanders operate at?

A

Stop working below 5kmh