; and (2) complete a work plan for implementing such recommendations. 107. Defect detection systems (a) In general Subchapter II of chapter 201 of title 49, United States Code, as amended by section 105(a)(1), is further amended by adding at the end the following: 20173. Defect detection systems (a) Definitions In this section: (1) Covered rail carrier The term covered rail carrier has the meaning given the term Class I carrier in section 10102. (2) Defect detection system The term defect detection system means the use of defect detectors, the analysis of the data defect detectors produce, and any other aspects a system that help railroads identifying and understand the severity of known safety conditions. (3) Defect detector The term defect detector means any device or equipment situated within the rail system that can detect and communicate a potential or known safety condition. (4) High-hazard train The term high-hazard train has the meaning given such term in section 20155(a)(6). (5) Main line The term main line means— (A) a segment or route of railroad tracks— (i) over which 5,000,000 or more gross tons of railroad traffic is transported annually; and (ii) that has a maximum authorized speed for freight trains in excess of 25 miles per hour