AR HB2004

Requires all railroad defect detectors to include hot box detectors, hot wheel detectors, and dragging equipment detector technology, with audible alarms broadcasting on assigned radio frequencies that report defect locations, axle counts, and train speed

Mandates hot wheel bearing detectors have sensitivity levels no higher than 110°F, and requires railroad corporations to notify the Arkansas Department of Transportation when detector repairs are needed

Establishes inspection procedures when trending defect detector technology identifies issues: first detection limits trains to 10 mph (hazardous materials) or 30 mph (non-hazardous); second detection requires immediate setout at nearest siding and qualified person inspection before movement

Creates civil penalties of $10,000-$25,000 per day for violations, with a one-time $500,000 penalty for grossly negligent violations or patterns causing imminent hazard, death, or injury

Provides railroad corporations 12 months from the effective date to retune all defect detectors within Arkansas to comply with the new requirements