Brake System Delhi Metro

Type of Brakes;

1. Service Brake: Electric Regenerative brake and Electro-Pneumatic (EP) friction brake blending, Load weighed and Jerk Controlled

2. Emergency Brake: EP friction brake, Load weighed

3. Parking Brake: Spring applied, air-release parking brake

4. Holding Brake: EP friction brake

5. BP (Brake pipe)-back up brake: Pneumatic friction brake 

Brake Blending - The Electric brake of each Motor car is used in preference to the pneumatic brake, as it works without wearing either brake blocks and is therefore more economical. The electric brake is controlled by the C/I (Converter/ Inverter),

In case that the Electric Regenerative brake cannot provide the braking effort as demanded by the master controller of the driver, the missing brake effort will be supplied by the pneumatic brake. This feature is called „blending“. The M car BECU on a two-car basis controls the brake blending. Blending is carried out between Motorcar and Driving trailer car of a unit.

Emergency Brake – The train set is equipped with an emergency brake loop wire. The emergency brake loop is connected to the emergency brake magnet valve, which is opened when de-energized and closed when energized (Fail-safe system). So, in case the emergency brake magnet valve is de-energized by interrupting emergency brake loop, the emergency brake will be applied automatically.

Holding brake - The holding brake is provided to prevent the train from rolling backwards on a rising gradient and the train from moving at the station.

The holding brake is released when C/I sends the signal “Reset Holding Brake” to the BECU. The tractive effort, which is applied when the signal “Reset Holding Brake Request” is initiated, shall ensure that the train will not roll backwards at a slope. The holding brakes are 70% of full service brakes.

Parking Brake – Parking brake is used for parking the train in depot and these are installed at Driving trailer car and Motor cars (1 set per axle).

Parking brake can be applied manually or these may apply automatically also when the MR pressure is low. To apply parking brake put Mode Selector at Standby position and press “Parking Brake On Push Button”. To release press “Parking Brake OFF Push Button”. Parking brakes are automatically applied in the event of loss of the main reservoir pipe pressure.


Parking Brake Manual Release - When MR pressure is low, it is possible to release individual parking brake manually from track level by; pulling out the manual release device installed at the parking brake cylinder. Operation of parking brake is monitored through the parking brake lamp installed at driver’s desk and TIMS screen. When the parking brake is applied the parking brake lamp will be illuminated and the application can be read through TIMS screen also.

Load Weighing – The load dependent pressure limiting valve (B3.C) is used to limit the supply reservoir air pressure according to the actual car load.

At the same time the average load signal is electrically fed to the BECU from the T pressure transducer on the EP-BCU. This signal is used for load compensation of the propulsion and airconditioning system.

    1 reviews
  • Rajdeep Janorkar

    Brake System Delhi Metro 5 months ago