Communications-Based Train Management (CBTM) incorporates Global Positioning Satellite (GPS) technology with an on-board train-control system to maximize railroad safety and operational benefits. By passing movement-related information and authority from a dispatching center to the on-board system, CBTM prevents a train from entering a block it is not authorized to occupy, enforces speed limits, protects track work areas and prevents running over misaligned switches. This integrated communications network constantly evaluates movement limits and required stopping distances to determine if the system needs to intervene. The locomotive engineer must respond appropriately to warnings and information transmitted from the dispatch center, or the CBTM system will begin braking automatically.

> Electronic Train Management System (ETMS)
> Electronically Controlled Pneumatic (ECP) Braking