The only subclass of the X72 was the X72A. As pointed-out by Jim Six in his Railroad Model Craftsman article, there appears to be no external distinction between the X72 and X72A. Both cars have same welded 12-panel construction and feature 6-panel Superior doors.

The X72 is a general purpose boxcar that can be found in nearly every service, making it a very common piece of equipment throughout North America. Some cars are equipped with DF Belt Loaders for assisting in loading and unloading of special equipment, while other cars are equipped with Dual Air Paks for in-shipment shock control of goods and pallets. These specially equipped cars are in assigned service to specific industries for specific loading

The Rapido X72 Boxcar features:

• Drawn from original blueprints and drawings
• Artworks sourced from original design drawings and photos
• Separate door posts, door latches and coupler cut levers
• Fully-detailed underframe including separate piping and equipment
• Detailed cushion draft gear with Kadee #158 whisker couplers
• Fully-detailed 70-ton trucks with 33” metal wheels