CFR›Title 49›Subtitle B›Chapter II›Part 234›Subpart D ContainsSubject groups Inspections and Tests–Requirements for Processor-Based SystemsCorpusDaily eCFRDisplayed edition2026-07-06Last updated2026-07-06 Subpart D—Maintenance, Inspection, and Testing Subject Groups Inspections and Tests Inspections and Tests Sections 234.247–234.273 Maintenance Standards Maintenance Standards Sections 234.201–234.245 Requirements for Processor-Based Systems Requirements for Processor-Based Systems Section 234.275 Previous C Subpart C—Response to Credible Reports of Warning System Malfunction at Highway-Rail Grade Crossings Next E Subpart E—Emergency Notification Systems for Telephonic Reporting of Unsafe Conditions at Highway-Rail and Pathway Grade Crossings