In this task, you are given a summary for US Congressional and California state bill, your task is to generate a Title for this bill. The preferred titles are under forty words and mention the purpose of the bill.

Positive Train Control Enforcement and Implementation Act of 2015 This bill extends deadlines and modifies requirements for railroad carriers and providers of intercity or commuter rail passenger transportation to implement positive train control (PTC) systems.  (A PTC system is a communications and signaling 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. Railroads which carry passengers or have high-volume freight traffic with certain hazardous materials are required to implement a PTC system.)  Within 60 days of enactment of this bill, each Class I railroad carrier (the largest operators by revenue) and provider of intercity or commuter rail passenger transportation must submit to the Department of Transportation (DOT) a plan for implementing PTC by December 31, 2018, instead of the December 31, 2015, deadline required under current law. DOT may extend the deadline if specified requirements are met.  The revised plan must include a detailed schedule and sequence for fully implementing PTC in a manner that complies with specified regulations, and railroads must implement PTC in accordance with the plan.  DOT may authorize a railroad carrier or other entity to begin the provisional operation of a PTC system without the required certification if it is necessary to enable the safe implementation of PTC in phases. 
Positive Train Control Enforcement and Implementation Act of 2015