Exhibit 21 UNION TANK CAR COMPANY AND SUBSIDIARIES SUBSIDIARIES OF THE REGISTRANT as of December 31, 1995 Jurisdiction Under Which Organized ------------------ Atlas Bolt & Screw Company Delaware Atlas Bolt & Screw Company of Canada, Inc. Ontario The Marmon Group of Canada, Ltd. Canada Procor Alberta, Inc. Alberta Procor LPG Storage, Inc. Alberta Procor Limited Canada Procor Sulphur Services, Inc. Alberta Rail Car Associates Limited Partnership Illinois Railserve, Inc. Canada Robertson Whitehouse, Inc. Ontario Trans Union Crane Rental, Inc. Canada Trans Union Fastener Corporation Delaware Trans Union Finance (Canada) Limited Ontario Uni-Form Components, Co. Delaware Union Tank Car Rail Services Company Delaware All subsidiaries listed above are wholly-owned except for Rail Car Associates Limited Partnership of which the Company is the general partner and has an 80% ownership interest and are included in the consolidated financial statements incorporated herein. -44-