Braking Systems and Types

Question 1

What is the AGTU

Answer 1

Air Generation Treatment Unit

Question 2

What are the 6 x Types of Brakes

Answer 2

Holding Brake
Emergency Brake
Light Brake
Parking Brake
Service Brake
Speed Limit Brake

Question 3

Which Brake is NOT a Friction/Pneumatic Brake

Answer 3

Speed Limit Brake

Question 4

Friction/Pneumatic Brake System

Answer 4

Wheel mounted disc brakes that apply pneumatic forces (friction) to the wheel to slow or stop the train. The pneumatic brake system does not require the assistance of the electrodynamic (electric) braking system.

Question 5

When is the Friction/Pneumatic Brake system the main braking system used.

Answer 5

When the train speed is more than 80km/h or under 5km/h

Question 6

Electrodynamic Brake System (Electric Brake)

Answer 6

A combination of regenerative and rheostatic braking. Electric Braking uses the electric traction motor as a generator when slowing the train

Question 7

When is the Electric (dynamic) Brake system the main braking system used.

Answer 7

When the train speed is between 5km/h and 80km/h dynamic brakes apply and interfere with the traction motors in motion

Question 8

Holding Brake

Answer 8

The train automatically applies the Holding brake to hold the train at a standstill. It prevents rollback when starting at a gradient.

Question 9

Emergency Brake

Answer 9

The Emergency Brake can be applied by the operator or by the train. It is used in safety related circumstances.

Question 10

Light Brake

Answer 10

The light brake is applied by the train. Traction and braking are being used simultaneously to align the train to the platform. Used when braking between 0-5km/h

Question 11

Park Brake

Answer 11

The park brake is applied by the operator. It is used when the train is being held for a period of time (stabling in SMTF) or to hold a train on a gradient. It will automatically apply when the air pressure falls below 4.5 bars.

Question 12

Service Brake

Answer 12

The service brake is controlled by the operator via the master controller. It is used to slow or maintain speeds on gradients, respect track speed limitations and stop at a station.

Question 13

Speed Limit Brake

Answer 13

The speed limit brake is applied by the train when a signal is received through ATC for a change in speed. If ATC is bypassed friction brake is used and Brake Control Electic (BCE) will limit the train to 25km/h. An EB will not activate.

Question 14

What is the Icon for a Rollingstock EB

Answer 14

A red blinking EB icon

Question 15

What is the Icon for a Signalling EB

Answer 15

A red square

Question 16

If an EB alarm is activated…

Answer 16

The operator will acknowledge the alarm and if it can be reset, the operator will do so through the DDU

Question 17

Rollback EB

Answer 17

A Rollback EB will be activated if a train rolls back more than 0.25m or at a speed faster than 0.25m/s

Question 18

Resetting EB after a Rollback

Answer 18

Place train in PM mode to attempt reset
If PM mode fails, place train in RM mode with TC permission
If unsuccessful, advise TC and request permission to move forward
Operate a short distance and stop
Request permission from TC to place the train back into PM mode

Question 19

What causes a Rolling Stock EB

Answer 19

ODDD activation
Train integrity lost to coupling
Low pressure in the main reservoir pipe - less than 6.5 bars
Master Controller EB activation
LV power supply is lost
Derailment
Deadman

Question 20

What caused a Signalling EB

Answer 20

EB activation bt CBTC/ATC
Overspeed
Passing PPI at stop
EDR activation at station
PEA activation at station
Evac Zone/Global Hold by TC
Rollback