Lightweight passenger cars required developments in steel processing that were not available until the 1920s and 1930s. By building passenger cars out of steel instead of wood, the manufacturers were able to build lighter weight cars with smooth or fluted sides and smooth roof lines.

Steel cars were ushered in at the beginning of the streamline era of the 1930s (although not all lightweight cars were streamlined) and steel has continued in use ever since then. With the use of steel for the car sides, railroads were able to offer more innovative passenger car types.

• Alaska Lightweight Cars
• Atlantic Coast Line Lightweight Cars
• ATSF (Valley Series) Lightweight Cars
• Baltimore & Ohio Lightweight Cars
• Canadian National Lightweight Cars

• Canadian Pacific Lightweight Cars
• Chesapeake & Ohio Lightweight Cars
• Chicago And North Western Lightweight Cars
• Commuter Railroad Lightweight Cars
• Great Northern Empire Builder Lightweight Cars

• Illinois Central Panama Limited Lightweight Cars
• Missouri Pacific Lightweight Cars
• New York Central Lightweight Cars
• Northern Pacific | North Coast Limited Lightweight Cars
• Pennsylvania Lightweight Cars

• Pullman Overland Lightweight Cars
• Southern Pacific Lightweight Cars
• Southern Pacific | Daylight Lightweight Cars
• Union Pacific Lightweight Cars
• VIA Lightweight Cars