Screen Reader Access Skip to Main Content Font Size   Increase Font size Normal Font Decrease Font size
Indian Railway main logo
National Emblem of India
Search :
View Content in Hindi

About Us


News & Updates

Areas Of Interest

Circulars, Letters, Concept Notes

Contact Us

Bookmark Mail this page Print this page


To promote use of Compressed Natural Gas (CNG) as a substitute for High Speed Diesel to create a clean environment in urban and semi-urban and to reduce cost of transportation while reducing dependence o­n imports.


Natural Gas is fast becoming a fuel of choice by the industry due to its inherent characteristics of low emission, clean burning and increasingly easy transportability. For the same calorific value, NG emits less CO2, particulates and NOx. It is also economical compared to liquid fuels. 

Government of India’s Policy

The government of India is promoting use of Natural Gas through incentives and liberal policies in import (OGL) and construction of pipelines. Building of international pipelines across Turkmenistan, Iran, Afghanistan and Pakistan are being explored to promote use of this cheap and clean energy source.

Indian Railways - Status

Indian Railways (IR) havetaken tentative steps in introduction of Natural Gas (in the form of CNG) as a fuel substitute o­n Diesel electric Multiple Units. There are nearly 700 Diesel Power Cars (DPC), which have the potential to be converted to dual-fuel mode. 


Trials with up to 20% substitution of high speed diesel with CNG have been successfully carried out. This is based o­n the “fumigation technology”. Fumigation involves mixing of natural gas in the charge air before supercharging and is generally limited to 20%

In-port Injection Technology involves injection of natural gas just before the opening of the inlet valve. This permits substitution of up to 60-65%. 

High Pressure Direct Injection (HPDI) technology permits up to 90-95% substitution. Gas is directly injected into the cylinder through an additional injector. A pilot injection of small quantity of high speed diesel is then made to initiate combustion. 

IROAF has planned retrofits with all three technologies. 

Natural Gas is safer than liquid fuels like diesel and petrol and LPG due to its smaller range of inflammability.

 State of the Industry

Most of the technology and equipment for retrofits are imported. HPDI is nearly proprietary. Conversion of an existing engine to dual-fuel, using any of the three technologies, involves extensive trials, mapping of engine characteristics at various levels of power, fuel substitution and safety related issues.


IROAF will introduce natural gas as a diesel substitute in all DEMUs sheds o­n IR. In addition, CNG will also be increasingly used o­n shunting locomotives to curb pollution in urban centres. IROAF will explore all available technologies such as Fumigation, In-port Injection, High Pressure Direct Injection (HPDI) and other emerging technologies to achieve these objectives.

Source : Indian Railways Organization For Alternate Fuels (IROAF) CMS Team Last Reviewed on: 29-09-2014  

  Admin Login | Site Map | Contact Us | RTI | Disclaimer | Terms & Conditions | Privacy Policy Valid CSS! Valid XHTML 1.0 Strict

© 2016  All Rights Reserved.

This is the Portal of Indian Railways, developed with an objective to enable a single window access to information and services being provided by the various Indian Railways entities. The content in this Portal is the result of a collaborative effort of various Indian Railways Entities and Departments Maintained by CRIS, Ministry of Railways, Government of India.