IGL signs MoU with Northern Railway to supply PNG to 22 Delhi-NCR railway establishments, replacing LPG and promoting cleaner energy. New Delhi: Indraprastha Gas Limited (IGL) has signed a Memorandum of Understanding (MoU) with the Delhi Division of Northern Railway to supply Commercial Piped Natural Gas (PNG) across 22 railway establishments in Delhi, Ghaziabad and Gautam Budh Nagar. The agreement is aligned with the government's National PNG Drive 3.