Canadian National Railway (CN) startled the liquefied petroleum gas (LPG) market in November when it issued an embargo on LPG tank cars heading toward the Edmonton, Alberta and Sarnia, Ontario natural gas liquids (NGL) fractionation and storage hubs. CN’s embargo included the requirement that shippers apply for permits for tank cars coming out of online storage. CN was doing what it needed to do. Simply put, an embargo prevents the creation of a waybill to generate the rail shipment of goods. When a shipper pulls together the order to create the waybill, the railroad’s data systems check for embargoes. If the destination is embargoed, the car cannot be shipped. The exception is if the railroad has established a permit system and the shipper has a permit number for the car(s). CN’s embargo will help the railroad manage the heavy, winter season LPG traffic, the railroad has said....