; table of contents. TITLE I—Rail Safety Sec. 101. Definitions. Sec. 102. Safety requirements for high-hazard trains. Sec. 103. Ensuring the safety of long trains. Sec. 104. Blocked highway-rail grade crossings. Sec. 105. Inspections. Sec. 106. Emergency brake signals. Sec. 107. Defect detection systems. Sec. 108. Safe Freight Act of 2023. Sec. 109. Increased penalties for violations of rail safety regulations. Sec. 110. Safer tank cars. Sec. 111. Rail safety infrastructure research and development grants. Sec. 112. Authorization of appropriations for tank car research and development. Sec. 113. Federal Railroad Administration safety culture. Sec. 114. GAO report on roadway worker protections. Sec. 115. Federal Railroad Administration safety workforce management. Sec. 116. Office of Personnel Management review of safety inspector and specialist classifications. Sec. 117. Alcohol and drug testing. TITLE II—Hazardous materials emergency response and preparedness Sec. 201. Hazardous materials registration fees. Sec. 202. Virtual training options. Sec. 203. Hazardous materials transportation emergency response and preparedness grants. Sec. 204. Emergency response assistance. I Rail Safety 101. Definitions In this title: (1) In general Except as otherwise provided, terms used in this title have the definitions given such terms in section 20155 of title 49, United States Code, as amended by section 102(a). (2) Secretary The term Secretary means the Secretary of Transportation. 102. Safety requirements for high-hazard trains (a) Tank car safety requirements Section 20155 of title 49, United States Code, is amended to read as follows: 20155. High-hazard trains (a) Definitions In this section: (1) Explosives The term explosives means Class 1 explosives categorized in Division 1.1, 1.2, or 1.3 (as such terms are defined in section 173.50 of title 49, Code of Federal Regulations). (2) Flammable gas The term flammable gas has the meaning given such term in section 173.115(a) of title 49, Code of Federal Regulations. (3)