Push-Pull Train In India

Introduction

A push-pull train configuration is a dynamic and versatile arrangement employed in locomotive-hauled trains, offering the flexibility of being driven from either end of the train. Push-pull trains are widely adopted in railway networks globally, catering to diverse needs such as long-distance travel, commuter services, and freight transportation. This introduction explores the key features and benefits of push-pull train configurations, highlighting their significance in modern railway operations.

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What is push pull train

A push-pull train refers to a configuration in which locomotives (engine) are attached at both ends and locomotives are interconnected through a wire train bus (WTB or Control cable) or through remote control, such as multiple-unit train control allowing train's operation in both directions without the need for turning the entire train around.

In this system, the Loco pilot in the front locomotive, referred to as the master locomotive, assumes control of the entire train. The rear locomotive, designated as the slave locomotive, operates in tandem with the commands issued by the master locomotive thus creating a synchronized and efficient operation. It enhances operational flexibility, accelerates response times, and contributes to overall safety and efficiency in railway operations.

Advantage of push-pull train

Push-pull train configurations offer several advantages in railway operations: 

• Bi-Directional Operation
• No shunting requirement at terminal station so cost-effectiveness.
• Operationally more feasible than train set
• Faster acceleration and de-acceleration
  
• Smoother operation and jerk free travel
• Low coupling forces so longer coupler life
• Improved Riding Comfort

Also Read: Amrit bharat Push-Pull Express Train

What is push pull technology in train

In train technology, "push-pull" refers to a configuration where a train can be driven from either end, eliminating the need for the locomotive to turn around at the terminal station. This is achieved in two ways: 

1. Two locomotives: One locomotive is located at each end of the train, with both drivers able to control the train's brakes, acceleration, and direction. This setup offers the most pushing power, making it ideal for heavy freight trains or trains climbing steep inclines. 

2. Locomotive and control car: This configuration features a locomotive at one end and a control car with a driver's cab at the other. The control car is typically an unpowered passenger car or a modified locomotive, connected to the locomotive by a data cable (wire train bus) or wireless communication system called the multiple-unit train control (MU) system. The driver in the control car can operate the entire train, including the locomotive's brakes and acceleration.

Wire train bus

The Wire Train Bus (WTB) is a communication system designed for passenger trains with variable compositions, typically consisting of up to 22 vehicles. It serves as a means of communication between different parts of a train, enabling coordination and control of various functions. Key features of the Wire Train Bus include: 

Medium: The WTB employs a duplicated shielded twisted pair cable that runs along the UIC cables between the train vehicles. 

Connector: The connection between vehicles is facilitated by the 18-pole UIC connector. To prevent oxidation, a current pulse, known as fritting, is applied during connection establishment. The standard connector for WTB nodes is typically a DIN 9-pin connector. 

Physical Level: The physical level of the WTB utilizes RS-485 levels with a data rate of 1 Mbit/s. The encoding involves a Manchester II code, and a HDLC (High-Level Data Link Control) frame protocol is used with proper voltage balancing to avoid DC components in the galvanic isolation transformers. 

Operation: The WTB operates cyclically with a deterministic operation period of 25 ms. This cycle is mainly used for traction control. Additionally, the WTB supports sporadic data transmission for diagnostics. 

Protocol Standard: The content of the periodic and sporadic frames is governed by the UIC 556 standard. To address the limited frame size, a version of TCP (Transmission Control Protocol) with reduced overhead, known as RTP (Real-Time Protocol), is used for message segmenting and reassembly.

First Push pull Train in India

• The first push-pull train in India was introduced on the Mumbai Suburban Railway initiated the use of push-pull operations to enhance the efficiency of local train services.
• Apart from suburban train, The Rajdhani Express operated by Central Railway (CR) from CSTM to NDLS has emerged as India's first train in adopting Push-Pull technology.
•  On 30-12-23 , Prime minister of India launched another two trains on Push-Pull configuration in the name of Amrit Bharat Express.

List of Train running with Push Pull technology

Trains running on Push-Pull configuration are as follows:

Sl. No.	Train No.	Train Name	Class
1	22221/22222	Mumbai CSMT - Hazrat Nizamuddin Rajdhani Express	1A, 2AC, 3AC
2	15557/15558	Darbhanga–Anand Vihar Terminal Amrit Bharat Express	Sleeper (SL)
3	13433/13434	SMVT Bengaluru-Malda Town Amrit Bharat Express (Weekly)	Sleeper (SL)