### Question
What does positive train control system mean?


### Answer
**Positive train control system** has the following meaning in *49 U.S.C. § 20157*:

> a system designed to prevent train-to-train collisions, over-speed derailments, incursions into established work zone limits, and the movement of a train through a switch left in the wrong position

#### Citation:
  - *49 U.S.C. § 20157*
  - Heading: **SUBTITLE V-RAIL PROGRAMS > PART A-SAFETY > CHAPTER 201-GENERAL > SUBCHAPTER II-PARTICULAR ASPECTS OF SAFETY**

