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Rail Capacity Workshop. A Primer on Capacity Principles New Technologies Public Sector Needs . SCORT/TRB Rail Capacity Workshop - Jacksonville Florida . SCORT/TRB Rail Capacity Workshop - Jacksonville Florida . 1. 1. Part 2:
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Rail Capacity Workshop • A Primer on Capacity Principles • New Technologies • Public Sector Needs SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 1 1
Part 2: Conventional Signaling and Train Control Technologies- A Primer • Signal and train control functions • Train control and dispatching • Signal systems and equipment • Capacity effects 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 2
Signal and Train Control Functions • Ensure Safety • Collision Prevention • Over speed prevention (some systems) • Train operations management • Set or authorize routes • Manage train priorities Advanced train control systems supplement and enhance, but do not replace these functions 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
Facilities and Installations • Central office • Dispatchers desks (work stations) • Remote switching (where available) • Track layout displays • Support software • Office to field communications (voice radio, “code line”) • Field installations • Wayside signals • Switches – powered and manual • Block systems • Track circuits • Interlockings – prevent conflicting signal and switch settings • Track-train communications (where applied) 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 4
Track Capacity Effects • Track capacity depends on the technical features of office and field systems, especially: • Block system types (manual, automatic, CTC) • Block lengths • Use of track circuits for train detection • Switch control – powered or manual • Train speeds – freight and passenger 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
Manual Block System (MBS) Manual Generation of Authorities Voice Transmission & Repeat (3-5 mins) Voice Location Reporting & Authority Release Manual Operation of Switches by Crew Low Capacity Operation – e.g. branch lines Dark Territory Station A Authority Limit Station B SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 6 22 September 2010
MBS With Automatic Block System (ABS) • Similar to MBS, except • Automatic Signals Protect Rear of Train • Roll up of Authority • Automatic detection of train using track circuits • Higher Capacity Operation – applied to lower traffic main lines Automatic Block Signals Station B Station A 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 7
Centralized Traffic Control • Consists of Signals & Switches operated by central dispatcher • Major advantage is avoiding manual switch delays Remote Control of Switches / Signals Supervisory Office Control and/or Indication 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 8
Centralized Traffic Control (cont) • Authority conveyed by Signal Indication • Track Circuits convey train location to dispatcher • Block system protects train in block • Much higher capacity • Better train performance • Applied to most higher capacity main lines on US freight network outside terminal areas 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 9
Braking Curves – Mixed Freight and Passenger Traffic • Block length is a function of freight train braking • Typically 2 – 3 miles length Higher Speed Passenger Speed Loaded Freight Passenger Or Commuter Block Design Distance 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 10
Wayside Signal Spacing Signal A4 Signal A3 Signal A2 Signal A1 Train 2 Train 1 Y G R G Block A1 Block A5 Block A3 Block A2 Block A4 Direction of Travel Block is occupied by train No Code Normal Speed Normal Speed Caution Speed Zero Speed Block length fixed by maximum speed, civil limits, grade, and worst train braking distance. 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 11
Signal Spacing - Options Signal A1 Signal A5 Signal A4 Signal A3 Signal A2 Train 2 Train 1 G/R Y/G G/R Y/R R/R Block A1 Block A2 Block A5 Block A3 Block A4 Block A6 Block is occupied by train Normal Speed No Code Normal Speed Advanced Approach Zero Speed Caution Speed Additional aspects provide finer control of train movement, at additional cost and complexity. Trains operating at different speed limits may require different rules. 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 12
Automatic Systems • Most conventional systems rely on engineer compliance with signals and operating rules • Automated systems provide in cab displays and may enforce compliance • Principal systems are: • Automatic Train Stop – ATS • Enforce braking if engineer fails to respond to signals • Normally 8 second delay before enforcement • Automatic Cab Signals - ACS • Automatic Train Control – ATC • Civil Speed Enforcement – NEC and some NJT only 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
Direction of Travel Signal Train Driver’s Panel Processor Signal Data Speedo Code Transmission in Rails Signal Data Data Code Brake Interface Code Pick-Up Coils Code Generator Cab Signals • Aspect transmitted display in engineer’s cab • Brakes apply automatically if authority is exceeded • Used on NEC, LIRR, MNCR, NJT, limited elsewhere • Two types: • Intermittent • Continuous 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 14 22 September 2010
No changes can occur while train is outside of limited intervals. Intermittent , ATS, ACS, ATC • Speed authorization is passed to train at limited • intervals, typically at signal locations. • Train stores information until next authorization is • received. 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 15
Continuous ATS, ACS, ATC • Speed authorization is continuously updated to • vehicle. • Changes in speed authority can be made at any • time, and are visible to operator immediately. • Capability to increase traffic; immediate recognition • of aspect upgrades allow quicker response. • Loss of signal is most restrictive, stopping train. • Train requires no ‘memory.’ 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 16
Signal A4 Signal A3 Signal A2 Signal A1 Train 2 Train 1 Y G R G Y Without ATP, Train 2 continues to slow throughout block, even though Train 1 proceeds past Signal A1. Signal A4 Signal A3 Signal A2 Signal A1 Train 2 Train 1 Y G R G Y G With ATP, Train 2 can resume normal speed as soon as Train 1 proceeds completely past Signal A1, increasing capacity Advantages of Continuous Automatic Systems 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 17
Intermediate Signals - Non-controlled signals other than distant signals – Aspect display cascades from next signal aspect. Most restrictive display is “Stop and Proceed.” Distant Signal - Last automatic signal before a home signal. Most restrictive display is usually “Stop and proceed.” Home Signal - Controls entrance into interlockings. Most restrictive display is “STOP.” Types of Signals 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 18
Types of Signal – Speed Signaling • Speed Signaling • Displays speed at this and next signal • Turnouts speeds displayed where applicable • Requires many signal aspects • Applied on the NEC Signals indicate authorized speed: 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 19
Signal Systems – Route Signaling • Route Signaling • Displays 3 or 4 Aspects • Clear , (double Approach), Approach to Stop & Stop • Diverging route, where applicable • Turnout speed is shown in timetable Signaling indicates selected route: 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 20
>20 Seconds Highway Crossing Protection Minimum warning time by state regulation or FRA is 20 seconds. 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 21
Highway Crossing Protection 20 seconds = 2933 feet at 100 MPH 80 seconds at 25 MPH FixedTrack CircuitApproach - Varies with train speed 20 seconds = 733 feet at 25 MPH 20 seconds – Any Speed Constant Warning- Grade Crossing Predictor Measures train speed and adjusts warning for constant warning time 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 22
Highway Crossing Protection Highway traffic signal pre-emption at nearby intersections. When train approaches, highway traffic signals prevent turns towards crossing , while allowing cars to clear crossing. 22 September 2010 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida SCORT/TRB Rail Capacity Workshop - Jacksonville Florida 23