ARRC Collision Avoidance System 2005 ASME/IEEE Joint Rail Conference March 16-18, 2005 Presented by Chinnarao Mokkapati Robert D. Pascoe Union Switch & Signal Inc.

Alaska Rail Road Facts (2003 Data) Employees 722 Year-round 10.8 average years of service 43.2 average age Operating Statistics 446,162 Passenger ridership 8,324,395 Freight tonnage 102,292 Revenue car loads Trains per day 33 Freights 14 Passenger - Summer 1 Passenger - Winter Operating Data Miles of track 466 main line 59 branch line 86 yards/sidings 611 Total Rolling Stock 1,625 Freight cars 42 Passenger cars 60 Locomotives Train Control ~500 miles of DTC ~30 miles of CTC

ARRC CAS Objectives PREVENT TRAIN TO TRAIN COLLISIONS BY ENFORCEMENT OF AUTHORITY LIMITS ENFORCE SPEED RESTRICTIONS PROVIDE PROTECTION FOR ROADWAY WORKERS AND EQUIPMENT IMPROVE EFFICIENCY OF OPERATIONS INCREASE CAPACITY

FRA Requirements Generation of safe mandatory directives Enforcement of authority limits Enforcement of speed restrictions Protection of Maintenance-of-Way workers and equipment Rule 236 Subpart H compliance required Performance Std: New system must be as safe or safer than the system being replaced Operating conditions, parameters, constraints must be defined Structured qualitative and quantitative assessment of safety (Base Case and New Case) required Product Safety Plan or Safety Case

Some Definitions CTC and DTC Operation

Some Definitions Track Bulletins Used in System

Collision Avoidance System

General Philosophy of CAD and OSS Subsystems Block 3 Block 6 Block 5 Block 7 Block 11 Block 9 Track Servers Existing Comms (( )) Dispatcher Work Stations Vital Independent Check of LOA, Bulletins CAD OSS

Vital Checks Done by OSS Via the OBC, the position of all trains are known to the OSS ‘Occupies’ Virtual blocks ‘un-occupies’ Virtual blocks Checks Bulletins associated with Blocks & LOA

OSS Hub Physical Architecture Microlok II RS423 Network Interface Adapter Ethernet CAD Subsystem Ethernet Switch OSS Hub Physical Architecture

Software in MicroLok II Units Block 1 Block 3 Block 6 Block 5 Block 7 Block 11 Block 13 Block 9 S#5 S#7 North Executive Software Operating System Application Processing Serial Communications Control Safety Diagnostics User Interfaces Event Logging Application Data Tables Track Sections defined as Virtual Blocks Switch locations Other identifiable points

OBC Requirements: Profile Generation Train Location and Speed Determination Digital Track Data Map Communication via Digital Radio

LOCATION AND SPEED DETERMINATION DGPS Accelerometers Tachometers Digital Map The result is that the OBC vitally determines its location on the rails and transmits its location to Central

New On Board Computer (OBC) - ATP

Existing Network Communication System

Communication Backbone

MONITORING DEVICES Rail Integrity Switch Position Signal Aspect in CTC

The Locomotive’s ATP Interrogates Three Wayside Devices using a short range data radio: A Rail Integrity Device Broken Rail Detection MicroTrax A Switch Position Device Normal or Reverse A Wayside Signal Device Aspect Locomotive Device Broken rail Short Range Data Radio Device N R Locomotive Short Range Data Radio Device Aspect Locomotive Short Range Data Radio

CAS Safety Assurance Safety resides in OSS and OBC, though CAD performs some safety-related functions OSS is implemented on US&S MICROLOK II Platform OBC implemented on US&S MICROCAB Platform These platforms use a combination of Inherent Fail-Safety and Diversity & Self-Checking safety architectures Certified by independent safety assessors Extensive service history

CAS Safety Assurance Compliance with FRA Rule 236 Subpart H Risk analysis of CAD-only DTC/CTC Operation (Base Case) Derive safety requirements for CAS V&V of CAS design and operation Risk analysis of CAS (CAS Case) Risk assessment Show CAS provides higher safety than CAD-only DTC/CTC operation

Risk Analysis Conduct Hazard Analyses Determine MTTHE using FFTA PHA O&SHA SSHA Determine MTTHE using FFTA

Derive safety requirements for CAS Potential hazards in Base Case FFTA of CAS elements CAS subsystem safety requirements

V&V of CAS design and operation Normal operation Systematic faults Random hardware faults Common Mode faults External influences

Risk analysis of CAS (CAS Case) Conduct Hazard Analyses PHA O&SHA SSHA Determine MTTHE using FFTA

Risk Assessment Show CAS provides higher safety than CAD-only DTC/CTC operation Submit PSP 20 elements required per FRA Rule 236.907

Project Timeline 11 / 2005 CAD SAT 06 / 2006 Office Safety and OBC FAT 2007 4/16/2005 - 10/16/2005 2005 Peak Season 4/15/2006 10/15/2006 2006 Peak Season 11 / 2005 CAD SAT Complete 2 / 2007 Revenue Service 10 / 2006 Office Safety and OBC SAT 06 / 2006 Office Safety and OBC FAT 1 / 2006 CAD Cutover complete 4Q 2004 System Definition

Conclusions CAS is a practical, relatively inexpensive PTC System Scalable for larger systems Uses proven safety architectures Credible, straight-forward safety proof