© Transportation Technology Center, Inc., a subsidiary of the Association of American Railroads, 2008

®

Positive Train Control (PTC) Positive Train Control (PTC) Applications in the USAApplications in the USA

Alan PolivkaAssistant Vice President

Communications and Train Control Technologies

Transportation Technology Center, Inc.Pueblo, Colorado - USA

TTCI is a Private, Non-Government Organization

© TTCI/AAR, 2008

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Recent Events relating to PTC Recent Events relating to PTC HIGH PROFILE ACCIDENTSHIGH PROFILE ACCIDENTS

““RAIL SAFETY IMPROVEMENT ACTRAIL SAFETY IMPROVEMENT ACT”” APPROVED BY CONGRESS:APPROVED BY CONGRESS:

““Each Class I railroad carrier and each entity providing regularlEach Class I railroad carrier and each entity providing regularly y scheduled intercity or commuter rail passenger transportation shall develop … a plan for implementing a positive train control system by December 31, 2015, governing operations on—

‘‘(A) its main line over which intercity rail passenger which intercity rail passenger transportation or commuter rail passenger transportation transportation or commuter rail passenger transportation ……;;

‘‘‘‘(B) its main line over which poison(B) its main line over which poison-- or toxicor toxic--byby--inhalation inhalation hazardous materials hazardous materials …… are transported; ... are transported; ...

The railroad carrier The railroad carrier shall implement a positive train control systemshall implement a positive train control systemin accordance with the plan.in accordance with the plan.””

OTHER CONSIDERATIONS OTHER CONSIDERATIONS ……

© TTCI/AAR, 2008

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Positive Train Control (PTC)Positive Train Control (PTC)(CBTC for North American Freight Railroads)(CBTC for North American Freight Railroads)

Dispatch Office

GPS

Movement Authorities

Network

High-Resolution Self-Positioning, Displays & Computers On Board Govern Train Movements & Speed iaw Limits Received from Off BoardHigh-Resolution Self-Positioning, Displays & Computers On Board

Govern Train Movements & Speed iaw Limits Received from Off Board

Location Reports

OnboardEquipment

Voice & Data Radios

ManagementInformation

System

Safety Functionality (per FRA)Prevent Train-to-Train CollisionsEnforce Speed Restrictions Protect Roadway Workers Operating Under Specific Authorities

No Track-BasedPositioningComponents

Server(Central orDistributed)

Wayside InterfaceDevice

(at Switches & Signals)

© TTCI/AAR, 2008

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PTC Architectures & ObjectivesPTC Architectures & Objectives

Initial implementations focus on improving Safety & Productivity.Subsequent objectives are to Reduce Infrastructure & Increase Capacity.

All must have a Solid Business Case ($).

Com

m-B

ased

Sig

nalin

g

Office Centric Distributed

Standalone• Vital

Overlay• Non-Vital

or • Vital

• Safety• Efficient Handling of

Unequipped Trains• Minimal Added

Wayside HW

• Safety• Efficient Handling of

Unequipped Trains

Four Different PTC Architectures:Four Different PTC Architectures:

• Safety• Least Wayside HW• Moving/Virtual Block• Homogeneous Arch.

• Safety• Virtual Block

© TTCI/AAR, 2008

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PTC Systems currently DeployedPTC Systems currently Deployedor under Development and Testor under Development and Test

In addition, Interoperable Communications-Based Signaling (ICBS)is being developed by a group of signaling suppliers with FRA support.

ETMS &

Derivatives

High Speed

Freight, predominantly

+ Passenger

Moving B

lock

Development110Columbia-Charleston, SCNSOTC

Test219Fort Worth, TX – Okla. City, OKBNSF/FRAETMS II

Revenue66Niles - Kalamazoo, MIAMTRAK/MDOT/FRAITCS

Development350Anchorage - Fairbanks, AKAKRR/FRACAS

Test46Chicago, IL –Rock Island DistrictMETRAETMS

Development48TTCI, Pueblo, CORRF/FRAV-PTC

Test32Columbus - Newark, OHOCRSOCRS PTC

Development108Columbia, SC - Charlotte, NCNSOTC

Development193North Platte - Morrill So., NEUPCBTC I

Development140Spokane, WA - Eastport, ID; Powder RiverUPVTMS

Revenue130Beardstown - Centralia, ILBNSF/FRAETMS I

Test153Hettinger, ND – Terry, MTBNSF/FRAETMS II

Revenue273Boston, MA - New York, NYAMTRAKACSES

Test157Hamlet, NC - Charleston, SCCSXCBTM II

Revenue87Hamlet, NC - Raleigh, NCCSXCBTM II

STATUS MI. RAIL CORRIDOR STAKEHOLDER PROJECT

© TTCI/AAR, 2008

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VitalVital--PTC ProjectPTC ProjectObjectivesObjectives

Develop & test a Vital PTC (VDevelop & test a Vital PTC (V--PTC) system with:PTC) system with:moving block capabilitymoving block capabilitypotential to reduce wayside hardwarepotential to reduce wayside hardware

lower cost to acquire, install & maintain (LCC)lower cost to acquire, install & maintain (LCC)less potential for vandalismless potential for vandalismhigher reliabilityhigher reliability

Provide public benefits throughProvide public benefits throughreduced accident risk, andreduced accident risk, andmore efficient national railroad network.more efficient national railroad network.

Address key PTC issues Address key PTC issues ……

VV--PTC is an R&D project being conducted by TTCI and PTC is an R&D project being conducted by TTCI and Lockheed Martin Corp. under sponsorship of the FRA.Lockheed Martin Corp. under sponsorship of the FRA.

© TTCI/AAR, 2008

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Issue Resolution↓

PTC Proliferation↓

Safety & Productivity Increases

• Enforcement Braking Algorithm Margin …...…..…

• Data Radio Performance …………….……………….……

• Interoperability ………………….…..…………..……

• Additional MoW Protection ……….……………………

• Track Discrimination at Train Initialization ……..…

• PTC Testing Challenges .……..……..…………..……

Current PTC IssuesCurrent PTC Issues

AEA, V-PTC& Test Bed

HPDR

HANDGPSUpgrade/Demo

HPDR, V-PTC& Test Bed

EIC PRT

FRA/TTCI Project:

Test Bed

© TTCI/AAR, 2008

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The Enforcement Braking IssueThe Enforcement Braking Issue

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ent B

rake

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licat

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et

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et T

arge

t

Offset (Margin)1750 ft

Typical Distributionof stopping points

Freight train stopping from 60 mph

Large Safety Margin in PTC Braking Algorithmscauses trains to Slow or Stop Sooner than Desired,

which has a negative effect upon Capacity.

Today’s predictive PTC enforcement algorithmsare based solely on wagon braking, assuming:

• No dynamic braking• No locomotive braking (except for short trains)• Worst case wagon braking parameters

• Train weight• Braking efficiency• Type of brake valve

© TTCI/AAR, 2008

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Solutions Proposed/Analyzed by TTCISolutions Proposed/Analyzed by TTCI

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d (m

ph)

Case 1Case 4Case 7Base Case20 Sec Warning40 Sec Warning

Case 1:Start of Current PTC Enforcement(Worst Case Assumptions)

Case 7:EmergencyOnly

Base Case:Nominal Train,

Normal Service Braking

Case 4: Less conservative train parameters

During full service enforcement, PTC monitors EOT brake pipe pressure & applies emergency braking only after reduction has reached EOT (train is bunched).

Also simulated grade scenarios, ECP, maintaining independent, …TOES Simulation by TTCI

Braking Distances – From 40 mph – 10 cars

© TTCI/AAR, 2008

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Study of InStudy of In--train Forcestrain Forces

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Concern: Will solutions that use emergency braking cause unsafe Concern: Will solutions that use emergency braking cause unsafe buff forces?buff forces?

TOES Simulations: Showed higher max buff inTOES Simulations: Showed higher max buff in--train forces (albeit gradual and train forces (albeit gradual and predictable) generated from normal (dynamic) braking than for prpredictable) generated from normal (dynamic) braking than for proposed oposed enforcement braking solutions including emergency brakingenforcement braking solutions including emergency braking

Emergency forces are less predictable, less uniform, and more dyEmergency forces are less predictable, less uniform, and more dynamic.namic.

Emergency inEmergency in--train forces are improved when emergency is train forces are improved when emergency is propagated from front propagated from front andand end of train using a 2end of train using a 2--way EOT deviceway EOT device

TOES Simulationby TTCI

© TTCI/AAR, 2008

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VV--PTC Braking Analysis SummaryPTC Braking Analysis SummaryPenalty enforcement based on worst case train characteristics caPenalty enforcement based on worst case train characteristics can n adversely affect train operations, especially at slow speeds andadversely affect train operations, especially at slow speeds and on on downgrades.downgrades.

PTC warnings and enforcement reduce total number of violations, PTC warnings and enforcement reduce total number of violations, emergency applications, and reduce their severityemergency applications, and reduce their severity

Currently, emergency applications are made by train crews in Currently, emergency applications are made by train crews in danger of violating authority limitsdanger of violating authority limits—— some of these trains were not bunchedsome of these trains were not bunched

With PTC enforcement, emergency application will only occur in With PTC enforcement, emergency application will only occur in rare cases and only when the train is bunchedrare cases and only when the train is bunched

Penalty enforcement with emergency backup allows better than Penalty enforcement with emergency backup allows better than worst case assumptions to be used, which:worst case assumptions to be used, which:

Reduces total number of enforcementsReduces total number of enforcementsReduces the negative impact on operationsReduces the negative impact on operationsFurther increases potential benefit of Moving BlockFurther increases potential benefit of Moving Block

Further Analysis, Simulation & Testingis Underway by TTCI

© TTCI/AAR, 2008

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Adaptive Enforcement Algorithm (AEA) ProjectAdaptive Enforcement Algorithm (AEA) Project(related TTCI project, sponsored by FRA)(related TTCI project, sponsored by FRA)

Test Controller/Logger Development

TOES Modifications

Parametric Study

Stage I: Base Case Enforcement Algorithm Development

Algorithm Development

Simulation Testing

Field Testing

Stage II: Propagation Time Corrective Algorithm Development

Algorithm Development

Simulation Testing

Field Testing

Stage III: Train Weight Corrective Algorithm Development

Algorithm Development

Simulation Testing

Field Testing

Stage IV: Brake Effectiveness Corrective Algorithm Development

Algorithm Development

Simulation Testing

Field Testing

Real-Time Adjustments of Braking Parameters

AEA Measures & Adapts to train’s actual:• Weight• Propagation Rate• Braking Efficiency

© TTCI/AAR, 2008

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PTC System PerformancePTC System Performance(traffic throughput) depends on (traffic throughput) depends on

Data Radio CharacteristicsData Radio CharacteristicsLost CBTC messages, due to contention, multipath,

noise, and interference, can stop trains.

Mean Distance Between Unnecessary Enforcements

1

10

100

1,000

10,000

0.95 0.90 0.85 0.80 0.75

PSM = P(1st try success)

Mile

s

HPDR Project is developing newstandard data radio for PTC et al.

AnalysisbyTTCI

© TTCI/AAR, 2008

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PTC System TestingPTC System Testing

System testing of new functionality in live, System testing of new functionality in live, operating environment is very difficultoperating environment is very difficult

Difficult or impossible to conduct Stress TestingDifficult or impossible to conduct Stress TestingOften Not RepeatableOften Not RepeatableMust accommodate Revenue TrafficMust accommodate Revenue TrafficMust obey all Operating Rules or obtain WaiversMust obey all Operating Rules or obtain WaiversChanges to Vital Equipment require Lengthy Changes to Vital Equipment require Lengthy V&VV&V

An onAn on--track Test Bed without revenue traffic track Test Bed without revenue traffic and regulations would alleviate these problems.and regulations would alleviate these problems.

© TTCI/AAR, 2008

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Communications & Train Control Test BedCommunications & Train Control Test BedTrains with PTC on boardTrains with PTC on board

real & simulatedreal & simulatedPTC Wayside UnitsPTC Wayside Units

at switches, signals, & at switches, signals, & crossingscrossingsreal & simulatedreal & simulated

PTC ServerPTC ServerRadio Base StationsRadio Base Stations

multiple, for handoffmultiple, for handoffEnvironment ControllerEnvironment ControllerDispatch SimulatorDispatch SimulatorMessage GeneratorsMessage GeneratorsInstrumentation for Instrumentation for Data CollectionData CollectionTime ServerTime Server

Related Systems:Related Systems:GPSGPS--based Vehicle based Vehicle Tracking (VTS)Tracking (VTS)DGPS DGPS –– Beacon Site Beacon Site NearbyNearbyHANDGPS in HANDGPS in ‘‘0909

48 miles (77 km) of Test Track on 52 mi2 (135 km2) of Land NE of Pueblo, CO

Rai

lroad

Tes

t

Trac

k

180’ Tower• MCC SDR• VHF Site Radio• ATCS• 452.465 MHz VTS• Microwave 6GHz T1

120’ Tower• VHF• ATCS

OperationsBuilding (OPS)• 802.11b/g• Microwave

6GHz T1

802.11b/g

CDMACellular

w/1xEVDO

802.11b/g

Test Loop Length & Max SpeedRTT – 14 mi. 165 mphTTT – 9 mi. 80 mphHTL – 3 mi. 40 mph

N

Tower & Antenna Locations

DGPS Coverage over the Test Bed

© TTCI/AAR, 2008

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VV--PTC Location Determination System PTC Location Determination System (LDS)(LDS)

TrackDiscrimination

Location Determination

GPSIn addition to GPS, Tachometer and Track Database, In addition to GPS, Tachometer and Track Database, VV--PTC LDS includes Gyros and Accelerometers.PTC LDS includes Gyros and Accelerometers.

Most other PTC systems do not include inertial sensors.Most other PTC systems do not include inertial sensors.No track tags (No track tags (BaliseBalise) required) required

MultiMulti--Sensor LDS Benefits:Sensor LDS Benefits:-- Higher Dependability Track DiscriminationHigher Dependability Track Discrimination-- Less Error from Wheel Slip/Creep/SlideLess Error from Wheel Slip/Creep/Slideduring GPS Lossduring GPS Loss

-- Better Fault DetectionBetter Fault DetectionImplemented by

Lockheed Martin Corporation

© TTCI/AAR, 2008

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OnOn--track Testing of Vtrack Testing of V--PTC LDS at TTCPTC LDS at TTCRoute Determination Tests (192 cases over Switches & Balloon LooRoute Determination Tests (192 cases over Switches & Balloon Loop)p)Position & Speed Accuracy Tests on RTT (16 test cases)Position & Speed Accuracy Tests on RTT (16 test cases)Direction & Movement Tests on RTTDirection & Movement Tests on RTTSlip Tests* (while accelerating)Slip Tests* (while accelerating)Slide Tests* (while braking)Slide Tests* (while braking)GPS Multipath TestsGPS Multipath TestsVV--PTC Server TestsPTC Server Tests

TTC Test Bed – Track Diagram

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602

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602

* Detergent applied to rail.

ALD Tag asInstalled Along Track

ALD Tag Reader asInstalled on Locomotive

© TTCI/AAR, 2008

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LDS POSITION ERROR RESULTSNO GPS OUTAGES – RTT LOOP

413 Samples Considered(requirement is ≤ 15 ft 99% Confidence)

Average offset = +0.155 ft 1 standard deviation of offsets = 3.85 ft99% (2.8 std dev) = 10.8 ft

RTT Loop - 8 Passes - Good GPS Coverage

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uenc

y

Frequency

© TTCI/AAR, 2008

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Feet Trav elled Along Track based on Integrated Tachom eter Pulses

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LDS Slide Test ResultsLDS Slide Test Results

RTT(Counter-Clockwise)

GPS Conditions - No GPS Satellites Tracked 7.5 minutes prior to slide to 2 minutes past slide

R13

R13.5

500 ftSoap Film

Slide 2 Start

Stop

braking

Integrated Tach Pulse Distance = 368.7 ftKnown Linear distance (survey) = 501.1 ft

In-track Tachometer Error = 132.4 ftLDS Error at R13 = 1.9 ft

R13.5

R13

“Slide 2” (from R13.5 to R 13 to Final Loco Rest Point 13” Past R13)Loco Accelerated to 10 mph from dead stop, then brought to stop 13” in past R13

© Transportation Technology Center, Inc., a subsidiary of the Association of American Railroads, 2008

®

Summary / ConclusionsSummary / Conclusions

Numerous PTC Systems are under Development, Testing or Revenue Operation

Architectures and Capabilities Vary

Issues are being Discovered and Resolved

Test Methods are Improving

Results are Encouraging – Development is Not yet Complete

TTCI is a Private, Non-Government Organization