Train line mileage

{
  "id": "MLC-T-TRA-000397",
  "term": "Train line mileage",
  "field": "Transportation",
  "definition": "The aggregate length of all line-haul railroads. It does not include the mileage of yard tracks or sidings, nor does it reflect the fact that a mile of railroad may include two or more parallel tracks. Jointly-used track is counted only once.",
  "references": [
    "National Transportation Statistics, Appendix B: Glossary"
  ],
  "url": "https://mlchart.com/terminology/transportation/train-line-mileage/"
}