(a) This part prescribes Federal safety standards for freight and other non-passenger train brake systems and equipment. Subpart E of this part prescribes Federal safety standards not only for freight and other non-passenger train brake systems and equipment, but also for passenger train brake systems. This part does not restrict a railroad from adopting or enforcing additional or more stringent requirements not inconsistent with this part.(b) Except as otherwise specifically provided in this paragraph or in this part, railroads to which this part applies must comply with all the requirements contained in this part.(c) Except for operations identified in § 232.3(c)(1), (4), and (6) through (8) , all railroads part of the general railroad system of transportation must operate pursuant to the requirements in subpart H of this part (which contains the requirements in this part 232 as they existed on May 31, 2001), until they are either required to operate pursuant to the requirements contained in subparts A through G of this part or the requirements contained in part 238 of this chapter. 66 FR 4193 , Jan. 17, 2001, as amended at 66 FR 9906 , Feb. 12, 2001; 85 FR 80570 , Dec. 11, 2020