Expert Article : Single Pipe Brake System drawbacks and How to overcome also with solution.

August 3, 2018 Articles

I want to dedicate this article to BMRCL Project Manager (Shri.J.Jha) and BMRCL DRSE (Shri N.M. Dhoke)

When I was working for BMRCL, DRSE and PM wants to bring new things in brake system of Bangalore metro they have asked me to study on single pipe brake system, during this study I have noticed few draw backs for single pipe brake system .

This article describes overview and how to overcome the draw backs with solution for single pipe brake system based on Indian climate Condition and working culture

Single pipe Brake system Overview

In market at present EP2002 brake module is with single pipe architecture most commonly used in Europe and in INDIA few projects have implemented.

EP 2002 — Integrated Mechatronic Modules

  • 100% Under floor mounted
  • All-In-One Solution including dump valves (WSP — Wheel Side Protection)
  • less piping, less wiring at car body
  • Brake Bus

EP2002 (back ground information)

  • mechatronic product approach
  • tested up to 70 °C
  • Highly integrated up and optimized solution for metro applications with distributed control, dump valves integrated
  • Standard Metro System with limited flexibility
  • No extended data logging possible
  • Transfer of pneumatic functionality
    (EP-Emergency Brake) towards Embedded electronics
  • EP2002 unit includes electric control function as Electric Brake Control Unit, pneumatic function as Brake Panel and Wheel Slide Protection function as antiskid valve
  • The unit is cube style and compact and light (“Plug and Play”).
  • Installation is done via pipe bracket and mounting bracket under floor.
  • It is possible to install close to the bogie. It is possible to reduce the piping and wiring.

Brake Control Concepts

EP2002 — Standard Control unit

  • de-central application
  • very compact design including dump valves
  • pneumatic and electronic components under floor
  • electronic standardized and tested up to 70 °C
  • highest level of integration
  • no brake pipe application possible
  • no local repair possible

PNEUMATIC SYSTEM

The pneumatic air distribution system is designed to fulfill the requirements of the different pneumatic sub-systems in the Vehicle. The system is divided into four sub systems, namely Air supply, Air distribution, Air quality and System controls.
1. Air supply: To generate the main air pressure for the pneumatic system.
2. Air quality: To condition the pneumatic air using Air dryer and filtration systems
3. Air distribution: To ensure all system have sufficient air pressure to fulfill their respective

Rescue Operation:

Indian Customer is more concern about rescue, how Rescue operation is carried out in single pipe brake system with less time

  • In Twin pipe brake system BackUP brake is used during rescue operation.
  • Single pipe rescue operation is explained below
  • Electrical connection between two trains can be done by Jumper cable connection

or

  • Small 10–15 pin auto coupling electrical connector

Auto coupler is best because for connecting jumper cable it takes time, by auto coupler time is reduced during rescue operation

If the project is with 3rd Rail system means auto coupler electrical connection is best

  • Time reduced to Switch OFF and Switch ON the third rail power supply is saved

Recuse Operation:

  1. Dead train should be coupled with healthy train with proper safety procedures.
  2. Once train is coupled , Electrical train lines get connected between trains by jumper or auto connector

Train line electrical signals

  • Motoring train line
  • Braking train line
  • Back up Switch train line (when operator selects switch default TCMS PWM signal will send to brake and propulsion system).
  • Parking brake (project specific)
  1. Once train coupled mechanically and Electrically –
  • MR pressure from healthy train is passed to dead train by MR Line
  • Releases brakes of dead train by electrically
  1. Release Parking brake (project specific) –
  • If project uses electrical train line , parking brake can be released by pressing push button

Or

  • If operator can release parking brake manually by pressing button of the parking brake magnetic valve ( value should have apply and release button)
  1. Train is ready to move — Motoring is done by train operator by TBC (Traction and brake controller) handle.

Note: Maximum motoring and Braking is possible

Main Disadvantage:

  • No local repair possible — Huge repair cost of the failure module.
  • Brake control unit (BCU)and Brake Electronic control Unit (BECU) come with one module and installed underframe
  • When all electrical brake fails ( worst case even Emergency Brake Loop fails )
  • In Twin Pipe brake system by discharging BP line Brakes are applied.
  • In Single Pipe brake system NO braking is possible

How to Over Come:

  • For End user Test Bench of BCU and BECU should be provided, so that user can replace the failure component and investigate the failed component.
  • BCU and BECU should be separate two modules because of Indian climate condition.
  • BECU should be installed inside the saloon area and BCU in under frame with High IP protection.
  • In worst condition if all electrical brake loop fails No Braking is possible.
  • Same like twin brake system introduce Pressure reducing valve ( Operator can discharge or vent out the MR pressure ) so that once pressure go below 7.5bar Emergency brake is applied .

Conclusion of Brake system:

If the above disadvantages are taken care with design modification, single pipe brake system will be more effective and user friendly for maintenance team.

  • Reduce weight.
  • Less maintenance.
  • Easy trouble shooting.
  • Less wiring.

Name : Chandan Kumar P

  • Bachelor of Engineering (B.E.) in Electronics & Communication Engineering in 2009.

As a Rail engineer with impressive 9+ years working experience in Rolling Stock + Signalling ,Design Engineering, Verification & Validation , System Specification , Testing & Commissioning , Maintenance , Modifications , Troubleshooting for various projects

My engineering forte is in Design, Schematics, pneumatic review, TCMS Interface, Signalling CBTC U400 system , Verification, Validation and Testing & commissioning.