• § 231.0 - Applicability and penalties.

• § 231.1 - Box and other house cars built or placed in service before October 1, 1966.

• § 231.2 - Hopper cars and high-side gondolas with fixed ends.

• § 231.3 - Drop-end high-side gondola cars.

• § 231.4 - Fixed-end low-side gondola and low-side hopper cars.

• § 231.5 - Drop-end low-side gondola cars.

• § 231.6 - Flat cars.

• § 231.7 - Tank cars with side platforms.

• § 231.8 - Tank cars without side sills and tank cars with short side sills and end platforms.

• § 231.9 - Tank cars without end sills.

• § 231.10 - Caboose cars with platforms.

• § 231.11 - Caboose cars without platforms.

• § 231.12 - Passenger-train cars with wide vestibules.

• § 231.13 - Passenger-train cars with open-end platforms.

• § 231.14 - Passenger-train cars without end platforms.

• § 231.15 - Steam locomotives used in road service.

• § 231.16 - Steam locomotives used in switching service.

• § 231.17 - Specifications common to all steam locomotives.

• § 231.18 - Cars of special construction.

• § 231.19 - Definition of “Right” and “Left.”

• § 231.20 - Variation in size permitted.

• § 231.21 - Tank cars without underframes.

• § 231.22 - Operation of track motor cars.

• § 231.23 - Unidirectional passenger-train cars adaptable to van-type semi-trailer use.

• § 231.24 - Box and other house cars with roofs, 16 feet 10 inches or more above top of rail. 1

• § 231.25 - Track motorcars (self-propelled 4-wheel cars which can be removed from the rails by men).

• § 231.26 - Pushcars.

• § 231.27 - Box and other house cars without roof hatches or placed in service after October 1, 1966.

• § 231.28 - Box and other house cars with roof hatches built or placed in service after October 1, 1966.

• § 231.29 - Road locomotives with corner stairways.

• § 231.30 - Locomotives used in switching service.

• § 231.31 - Drawbars for freight cars; standard height.

• § 231.33 - Procedure for special approval of existing industry safety appliance standards.

• § 231.35 - Procedure for modification of an approved industry safety appliance standard for new railcar construction.