What is a train Axle?
A rod or spindle (either fixed or rotating) passing through the centre of a wheel or group of wheels
What is a Bogie?
A structure underneath a railway vehicle (wagon, coach or locomotive) to which axles (and hence wheels) are attached through bearings.
How many motor & trailor bogies are on a complete 6 car metro train?
- 8 Motor Bogies
- 4 Trailer Bogies
What does a Bogie Isolation Switch do?
Where are these found?
Used to isolate bogies of the concerned car when required and with authorisation from TC.
Found to the RHS of door 4 in every car.
What are the 6 different braking types?
- Holding Brake
- Emergency Brake
- Light Brake
- Parking Brake
- Service Brake
- Speed Limit Braking
H.E.L.P.S.S.
What are the 2 different braking systems?
(name the systems only)
- Friction Brake (pneumatic)
- Electrodynamic Brake (electric brake)
What is Friction Brake (pneumatic)?
At what speeds is this brake used?
Friction brake is achieved by means of wheel-mounted brake discs and can slow or stop train without the assistance of the electrodynamic braking system. Reliant on pneumatic forces to apply the wheel-mounted disc brake to the wheel.
Used when speed is below 5kph, and over 80 kph
What is Electrodynamic Brake (electric)?
At what speeds is this brake used?
A combination of regenerative and rheostatic braking. Dynamic braking uses the electric traction motor as a generator when slowing down the train.
Used when speed is between 5kph and 80kph
What is the Holding Brake?
Used when the train is to be safely maintained in standstill conditions, such as passenger loading/unloading.
Prevents rollback when starting a movement on a gradient. The brake is released when enough propulsion is applied.
What is the Emergency Brake?
Used in case of safety-related conditions, either when the service brake has failed or when the shortest stopping distance is required, such as potentially dangerous or emergency situations.
Emergency Brakes are applied either by a rolling stock EB, or a Signaling Emergency EB (both indicated as alarms on the TCMS screen).
The train operator must acknowledge an EB alarm on the TCMS (DDU screen) and reset the EB Brake before moving the train.
What are the causes of a Rolling Stock Emergency Brake?
- ODDD (Obstruction & Derailment Detection Device activated
- Train integrity lost to uncoupling
- Low pressure detected in main air pressure (below 6.5 bar)
- Emergency button / master controller EB
- Low voltage power supply lost
- Derailment
- Deadman switch feature
What are the causes of a Signalling Emergency Brake?
- Activated by CBTC/ATC
- Overspeed
- Passing PPI at stop
- Emergency Door release activation at station
- PEA Alarm at station
- Evacuation zone / Global hold by TC
- Rollback
What is the Light Brake?
At what speed is this brake used?
A term used when both traction and braking are used simultaneously to align the train on a platform.
Used at speeds between 0 - 5kph.
How far does a train need to roll back before the EB is applied?
Besides the EB alarm on the train DDU, what else will happen with this type of EB?
25cm.
An alarm will activate at the ATS workstation in the OCC
What is the Park Brake?
A component of friction braking, used when the train is to be held for a period of time such as stabling or to hold the train on a gradient.
The Park Brake will apply automatically when the main air pressure falls below 4.5 bars.
What is the Service Brake?
A combination of friction and electrodynamic braking systems, used to:
- Slow down or maintain train speed on gradients
- Respect track speed limitations
- Stop at a station
The operator applies and controls the Service Brake via the master controller.
What is the Speed Limit Brake?
When a signal is received through the ATC for a change in speed, electrodynamic braking is utilised to lower the speed.
If ATC has been bypassed, friction brake is used and Brake Control Electric (BCE) will limit the train to 25kph.
What is the Setting Back procedure?
Required when a train long docks, and needs to back up to line up with PEBs.
- Bring train to stop - full service brake.
- Radio TC, advise trainset XX has overdocked by xx meters, and request permission to put train into RMR.
- TC gives permission, repeat back intructions as per critical comms.
- Reverse train back to dock correctly at service stopping point (SSP)
- Confirm with TC you have docked correctly. Request permission to put train into PM, and follow TC orders.
What is the procedure to Pass Signal at Stop?
(MSG 608 passing signal at stop)
- Stop at the signal / PPI at stop
- Radio TC, advise location (e.g. SI-3112) and request permission to proceed past PPI at stop
- TC givers authorisation - repeat back instructions as per critical comms
- Checkpoints are set correctly before moving
If this procedure is not followed, a formal SPAD (Signal Passed at Danger) investigation will be required
What is AGTU?
Air Generation & Treatment Unit.
Generates moisture free compressed air pneumatic on the train such as braking, auxilary reservoir and suspension system.
What types of brakes use Pneumatic braking system?
*Holding Brake
*Emergency Braie
*Light Brake
*Park Brake
*Service Brake
(All types except Speed Limit)
