	Introduction

Following several high-profile train incidents, Congress passed the Rail Safety Improvement Act of 2008 (RSIA08; P.L. After freight and commuter railroads raised concerns about their ability to meet the 2015 deadline, Congress extended the deadline by three years to December 31, 2018, or up to two years beyond that for certain qualifying railroads ( P.L. As of July 2018, it appears that all railroads will seek qualification for extending the deadline. This system is called automatic block signal (ABS), and is generally the most sophisticated signal system used by freight railroads where PTC has not been installed. Rail-Related Fatalities

Most rail-related fatalities are caused by pedestrians trespassing on railroad tracks or motor vehicles being hit at grade crossings. The bill also would have allowed railroads to implement alternative strategies on track that does not transport passengers where the "alternative risk reduction strategy that would reduce the risk of release of poison- or toxic-by-inhalation hazardous materials to the same extent the risk of a release of poison- or toxic-by-inhalation hazardous materials would be reduced if positive train control were installed on those tracks." 114-73 ), enacted October 29, 2015, extended the deadline for PTC implementation from December 31, 2015, to December 31, 2018. A more expansive variant of an overlay-type system is communications-based train control (CBTC). For example, the real-time, two-way communication of train locations combined with speed restrictions and moving authorities can lead to more efficient scheduling, increased capacity, and fuel savings. Implementation

Based on progress reports submitted by railroads to the FRA, the FRA surmises that only four railroads (BNSF and Union Pacific, and the Los Angeles and Philadelphia area commuter railroads) will likely have fully installed the necessary PTC equipment by the end of 2018, but even these railroads would likely need an extension because other railroads operating over their lines would not be fully PTC-compliant. Cost and Benefits

In 2009, the FRA estimated the total capital cost of wayside, on-board, radio, and office equipment necessary for full PTC deployment on all affected railroads to be in excess of $10 billion. However, the federal government has provided assistance. Although many serious incidents due to error by train engineers or dispatchers could be prevented by PTC, PTC is expected to prevent less than 2% of the approximately 2,000 railroad collisions and derailments that occur annually. This then may lead to social benefits such as reductions in fuel consumption and truck accidents. In addition to capital costs, operating and maintenance costs will increase as well. Another barrier to market entry could arise from the need for interoperability and spectrum compatibility. A February 2018 NTSB board meeting discussing this and a similar incident noted that PTC is not a technology well-suited to a terminal environment, due to the extremely short stopping distances and the inability for trains in tunnels to send and receive GPS signals.
The Rail Safety Improvement Act of 2008 (RSIA08) requires implementation of positive train control (PTC) on railroads which carry passengers or have high-volume freight traffic with toxic- or poisonous-by-inhalation hazardous materials. PTC is a communications and signaling system that has been identified by the National Transportation Safety Board (NTSB) as a technology capable of preventing incidents caused by train operator or dispatcher error. PTC is expected to reduce the number of incidents due to excessive speed, conflicting train movements, and engineer failure to obey wayside signals. It would not prevent incidents due to trespassing on railroads' right-of-way or at highway-rail grade crossings, where the vast majority of rail-related fatalities occur, and might not work well in some passenger terminal areas.
Under RSIA08, PTC is required on about 60,000 miles of railroad track. The Federal Railroad Administration (FRA) estimates full PTC implementation will cost approximately $14 billion. Progress among railroads in installing and operating PTC is mixed: a few large freight and commuter railroads show substantial progress while many others show much less progress. Federal funding provided thus far includes about $2 billion in loans and grants, mostly for commuter lines. After freight and commuter railroads raised concerns about their ability to meet the December 31, 2015, deadline in RSIA08, Congress extended the deadline by three years to December 31, 2018, or up to two years beyond that for certain qualifying railroads (P.L. 114-73). A July 2018 FRA report indicates that possibly all railroads will seek to qualify for an extension beyond the December 31, 2018, deadline, mostly for completing testing of their PTC systems.
PTC uses signals and sensors along the track to communicate train location, speed restrictions, and moving authority. If the locomotive is violating a speed restriction or moving authority, on-board equipment will automatically slow or stop the train. A more expansive version of PTC, called communications-based train control (CBTC), would bring additional safety benefits plus business benefits for railroad operators, such as increased capacity and reduced fuel consumption. However, CBTC is not currently being installed by any U.S. railroad, due to the additional cost and the challenge of meeting implementation deadlines.
In addition to funding requests for maintaining the PTC systems, Congress may be confronted with issues related to interoperability and barriers to market entry as railroads work toward implementing PTC.