Tuen Mun

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• Tuen Mun Yuen Long LRT
• Traffic Control System
• 20th April 2007
• Prepared by Michael Chiu

P26180/PS/PS140405.PPT/LLH/13APR05
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• Introduction
• LRT / Road Traffic Control System
• LRT Detection System
• Signal Operation
• Features of Traffic Signal Controller

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Introduction

• The KCRC Light Rail Transit (LRT) was
  commissioned in 1988 and the system was further
  expanded between 1991, 1993 and 2003.
• The current daily passenger volume is about
  400,000 which serving Tuen Mun, Yuen Long and Tin
  Shui Wai of over 1 million of population.

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Tuen Mun Yuen Long LRT System

• In year 1988, the Phase 1 LRT/Road Traffic
  Control System was installed in Tuen Mun and Yuen
  Long Areas to provide priority traffic control
  for Light Rail Vehicles. The System was further
  expanded to Tin Shui Wai in years 1993 and 2003.

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KCRC Light Rail Transit (LRT)
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Basic Operation and Control Principles

• The Light Rail Vehicle (LRV)
• Vehicle actuated for road traffic
• Priority control for LRV
• suffer minimum delay
• pass through junction without slowing down

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LRT / Road Traffic Control System Schematic
Diagram
LRT Signalling System
LRT Request Detectors
LRT Request (max 8 nos.) and Interrogator Fault
Signals (max 2 nos.)
LRT Request (max 8 nos.) and Interrogator Fault
Signals (max 2 nos.)
Vehicle Detection Loops
LRT Interrogator Unit
LRT Cancel Detectors
Push Button Units
Traffic Controller Fault Signal (1 no.)
Traffic Signal Controller
LRT Interface Unit
Traffic Controller Fault Signal (1 no.)
LRT Signal Lamps Drive (max 8 sets)
Lamp Drive to Vehicular and Pedestrian Signals
LRT Signal Lamps Drive
LRT Proceed Signal (max 8 sets)
Note If the period of a LRT request signal is
shorten than 4 seconds, it will be treated as an
artifical request
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Detection System

• Road traffic detection
• Inductive loop detector
• Infra-Red detector
• Demand Right-of-Way
• To Extend Green time to Preset Maximum Green
• Pedestrian Traffic Detection
• Push Button
• Demand Right-of-Way
• LRV Detection
• Individual LRV identity
• Request detector
• Cancel detector

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Inductive Loop Detector
Inductive Loop Detector
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Inductive Loop Detector
Inductive Loop Detector
Concrete Slab
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Alternative Vehicle Detector
Infra-red Detector
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LRV Request Detector
LRV Request Detector
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LRV Cancel Detector
LRV Cancel Detector
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LRT Signals
LRV Signal
Junction Speed Indicator
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Timing Periods of LRV on Approach to Stop Line
Critical service braking point
Flashing proceed period
First delay
Prevent
Road junction
Min. green (C)
Intergreen (B)
Braking time (A)
Intergreen (D)
LRV Stop line
Priority demand
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LRT Detection System

• LRV Request / Cancel Detectors
• To detect the vehicle number and route number of
  every LRV
• LRT Interrogator Unit
• Processes the LRT request and cancel signals
• Create LRT request signals to traffic signal
  controller

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LRV Request Detector

• LRV request detector will be located at the
  latest position to permit the LRV to proceed
  through the junction without being stopped for
  traffic signals.
• The location of every request detector would be
  determined by
• LRV Speed Profile
• Intergreen timings between phases
• LRT Stop and track point

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Process of LRT Request Signal

• LRT Interrogator detects the vehicle number and
  route number of each LRV and produce a request
  signal for a particular LRV movement phase.
• The Interrogator stores information on any LRVs
  which passed a request detector and have not yet
  passed the junction and cancel detector.
• The request signal will be ended when the last
  requested LRT train reaches the cancel detector.

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LRT Proceed Signal
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Features of Traffic Signal Controller

• Provide inputs for
• Maximum 8 Nos. of LRT requests, and
• Maximum 2 Nos. of Interrogator Fault Signals
• Provide output for
• 1 No. of Controller Fault
• Total 15 sets of Lamp Drive, in which maximum 8
  sets of Lamp Drive can be provided for LRT Phase

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Features of Traffic Signal Controller

• Provide LRT Priority Mode
• LRV have priority in gaining and holding
  Right-of-Way over other vehicles
• Priority LRV demand will curtail the extension
  time of the current VA phases, and skip all the
  VA demands in order to move to the stage that
  constituting the demanded priority phase
  immediately

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Features of Traffic Signal Controller

• Provide Priority Phase
• Non-fixed Phase
• Non-Latching Demand During Inter-stage Period
• Maximum Green Periods, consists of
• VA Maximum Green Period
• Priority Maximum Green Period
• Four sets of VA maximum and priority maximum
  times are provided for each LRV priority phase

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Features of Traffic Signal Controller

• LRT first and second delay periods
• Provide LRT first and second delay periods to
  delay processing of LRV request signals.
• When LRT first delay starts, Detector Fault
  Monitoring (DFM) facility will be run to monitor
  the duration of that LRT request.
• During the second delay, a stage change is
  prevented except to the stage that constituting
  the specified LRV phase.
• After expiry of the LRV first and second delay, a
  priority demand will be inserted to the
  associated LRV Phase Movement.

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Features of Traffic Signal Controller

• LRT first and second delay periods
• Provide LRT first and second delay periods to
  delay processing of LRV request signals.
• When LRT first delay starts, Detector Fault
  Monitoring (DFM) facility will be run to monitor
  the duration of that LRT request.
• During the second delay, a stage change is
  prevented except to the stage that constituting
  the specified LRV phase.
• After expiry of the LRV first and second delay, a
  priority demand will be inserted to the
  associated LRV Phase Movement.

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Phase Compensation

• If a VA phase is curtailed by LRV priority, an
  extension of the VA maximum time of that VA phase
  may be introduced next time when it gains right
  of way.
• Four different sets of compensate timers can be
  configured in associated with the LRT phase to
  cope with the AM peak, PM peak, Off-peak and
  Fault Mode operations

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Extended Intergreen Period

• Extended Intergreen Period shall be run after an
  LRT phase under the following conditions
• 1. If there is an outstanding LRT demand
• 2. If there is an LRT fault, priority DFM or
  artificial request
• 3. If the controller is in fixed time or manual
  modes.

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Extended Intergreen Period (Contd)

• Extended Intergreen Period shall be terminated
  when either
• 1. The outstanding LRT demand has been cleared
  or
• The Extended Intergreen Period has been extended
  to its maximum value.

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Extended Intergreen Period (Contd)

• An optional facility (Flexible All Red Facility)
  can be provided for complicated junction with
  several LRV phases and LRV stages.
• The traffic controller can select 6 different
  Extended Intergreen periods in accordance with
  the phase to phase and stage to stage movements
  taking place.

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LRT First Come First Serve Facility

• In general the controller will serve the Priority
  demands in cyclic order.
• At some junctions one LRV approach may be used by
  2 LRVs which turn in different directions at the
  junction, it may need to use First Come First
  Serve Logic to serve the LRV demands in the order
  of sequence of arrival.

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LRT Service Order Facility

• The traffic controller will remember which V.A.
  stage was served before the priority stage, and,
  if there is a V.A. demand move to the next stage.
• The stage sequence of this example junction would
  be
• Stage 1gtStage 2gtStage 1gt
• Stage 3gtStage 1gtStage 4gt
• Stage 1gtStage 5

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Detection of LRT Faults

• The traffic controller detects 3 types of LRT
  faults, including
• - Interrogator Fault
• - Artificial Request
• - Priority DFM
• The traffic controller will also count the
  numbers of the LRT faults, and time the fault
  durations.

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LRT Fault Mode Operation

• When LRT fault (Artificial Request, Priority DFM
  or Interrogator Fault) is detected, the traffic
  controller will enter Fault Mode Operation, and
  take the following actions
• 1. Disable priority operation for the faulty
  request.
• 2. Insert permanent demand to the faulty LRT
  phase.
• 3. Every time the faulty LRT phase terminates,
  the controller will insert Extended Intergreen
  Period and extend to the maximum.
• 4. Run the Fault Mode Plan (with shorter cycle
  time) when the Interrogator fails or serious LRT
  detector failures is detected.
• The fault mode operation will be self-reset after
  the LRT fault has been cleared.

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LRV Signal Timings
Constant Junction Speed
LRV Speed Profile
braking
Stop
Stop
Direction of Travel
Min Green
Inter- Green
Inter- Green
Braking Time
1st Delay
Green Proceed
Flashing Proceed
Prevent/2nd Delay
T
Priority Demand
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LRV Speed Profiles

• P-way Alignment Diagram
• Acceleration/Deceleration Characteristic Tables
• Speed Restrictions at Curves

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Permanent-way Alignment Diagram
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LRV Acceleration/Deceleration Characteristic
Tables
Acceleration / Deceleration Distance (in metre)
Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed
Initial Speed 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 Initial Speed
0 0.8 3.2 7.2 12.9 20.1 28.9 39.4 62.6 97.9 134.6 175.1 219.4 267.7 319.8 0
50 3.5 2.4 6.4 12.1 19.3 28.1 38.6 61.8 97.1 133.8 174.3 218.6 266.9 319.0 5
10 7.0 3.5 4.0 9.7 16.9 25.7 36.2 59.4 94.7 131.4 171.9 216.2 264.5 316.6 10
15 11.2 7.7 4.2 5.7 12.9 21.7 32.2 55.4 90.7 127.4 167.9 212.2 260.5 312.6 15
20 15.5 12.0 8.5 4.3 7.2 16.0 26.5 49.7 85.0 121.7 162.2 206.5 254.8 306.9 20
25 22.8 19.3 15.8 11.6 7.3 8.8 19.3 42.5 77.8 114.5 155.0 199.3 247.6 299.7 25
30 30.0 26.5 23.0 18.8 14.5 7.2 10.5 33.7 69.0 105.7 146.2 190.5 238.8 290.9 30
35 40.5 37.0 33.5 29.3 25.0 17.7 10.5 23.2 58.5 95.2 135.7 180.0 228.3 280.4 35
40 51.0 47.5 44.0 39.8 35.5 28.2 21.0 10.5 35.3 72.0 112.5 156.8 205.1 257.2 40
45 63.5 60.0 56.5 52.3 48.0 40.7 33.5 23.0 12.5 36.7 77.2 121.5 169.8 221.9 45
50 75.5 72.0 68.5 64.3 60.0 52.7 45.5 35.0 24.5 12.0 40.5 84.8 133.1 185.2 50
55 90.8 87.3 83.8 79.6 75.3 68.0 60.8 50.3 39.8 27.3 15.3 44.3 92.6 144.7 55
60 106.0 102.5 99.0 91.8 90.5 83.2 76.0 65.5 55.0 42.5 30.3 15.2 48.3 100.4 60
65 123.0 119.5 116.0 111.8 107.5 100.2 93.0 82.5 72.0 59.5 47.5 32.2 17.0 52.1 65
70 141.0 137.5 134.0 129.8 125.5 118.2 111.0 100.5 90.0 77.5 65.5 50.2 35.0 18.0 70
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed
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LRV Acceleration/Deceleration Characteristic
Tables
Acceleration / Deceleration Time (in second)
Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed
Initial Speed 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 Initial Speed
0 1.2 2.3 3.5 4.6 5.8 6.9 8.1 10.3 13.3 16.1 18.9 21.7 24.4 27.2 0
50 1.1 1.1 2.3 3.4 4.6 5.7 6.9 9.1 12.1 14.9 17.7 20.5 23.2 26.0 5
10 2.2 1.1 1.2 2.3 3.5 4.6 5.8 8.0 11.0 13.8 16.6 19.4 22.1 24.9 10
15 3.3 2.2 1.1 1.1 2.3 3.4 4.6 6.8 9.8 12.6 15.4 18.2 20.9 23.7 15
20 4.4 3.3 2.2 1.1 1.2 2.3 3.5 5.7 8.7 11.5 14.3 17.1 19.8 22.6 20
25 5.5 4.4 3.3 2.2 1.1 1.1 2.3 4.5 7.5 10.3 13.1 15.9 18.6 21.4 25
30 6.6 5.5 4.4 3.3 2.2 1.1 1.2 3.4 6.4 9.2 12.0 14.8 17.5 20.3 30
35 8.1 7.0 5.9 4.8 3.7 2.6 1.5 2.2 5.2 8.0 10.8 13.6 16.3 19.1 35
40 9.0 7.9 6.8 5.7 4.6 3.5 2.4 0.9 3.0 5.8 8.6 11.4 14.1 16.9 40
45 9.8 8.7 7.6 6.5 5.4 4.3 3.2 1.7 0.8 2.8 5.6 8.4 11.1 13.9 45
50 10.8 9.7 8.6 7.5 6.4 5.3 4.2 2.7 1.8 1.0 2.8 5.6 8.3 11.1 50
55 11.7 10.6 9.5 8.4 7.3 6.2 5.1 3.6 2.7 1.9 0.9 2.8 5.5 8.3 55
60 12.6 11.5 10.4 9.3 8.2 7.1 6.0 4.5 3.6 2.8 1.8 0.9 2.7 5.5 60
65 13.5 12.4 11.3 10.2 9.1 8.0 6.9 5.4 4.5 3.7 2.7 1.8 0.9 2.8 65
70 14.4 13.3 12.2 11.1 10.0 8.9 7.8 6.3 5.4 4.6 3.6 2.7 1.8 0.9 70
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed Target Speed
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LRV Speed Restrictions Table
Speed Curve Radius Without Cant Curve Radius With Cant
0 -- --
5 -- --
10 11 --
15 20 11.0
20 32 16.6
25 50 25.1
30 71 31.6
35 97 47.4
40 126 62.0
45 160 77.5
50 197 93.8
55 238 113.6
60 284 135.7
65 333 160.0
70 386 186.4
75 443 214.6
80 503 284.0
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Enhanced LRT Facilities

• KCRC has installed a new LRT Signalling System
  for Tin Shui Wai Phase IV Extension in December
  2003. It is scheduled to replace the existing LRT
  Signalling System in Tuen Mun, Yuen Long and Tin
  Shui Wai areas by end 2005 or early 2006.
• The new LRT Signalling System has incorporated
  some new facilities to enhance the operation of
  the system.
• Subject to the approval of TD, the Enhanced LRT
  facilities might be implemented along with the
  new Signialling System. If it happens, the future
  ATC System should take account of the Enhanced
  LRT facilities.

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Efficiency

• Latched / unlatched demand
• Compensation time
• Flexible all red facility
• Variable Dwell Time

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Latched/Unlatched Demand

• Latched Demand
• - The demand remains active until the phase or
  stage is served.
• Unlatched Demand
• The demand is cleared if the demand condition
  ceases before the phase or
• stage is served.

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Compensation Time

• If a VA phase is curtailed by LRV priority, an
  extension of the VA maximum time of that VA phase
  may be introduced next time when it gains right
  of way.
• 4 different sets of compensate timers can be
  configured in associated with the LRT phase to
  cope with the AM peak, PM peak, Off-peak and
  Fault Mode operations.

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Phase Compensation
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