1. p-REES 2: Module 2-B Advanced Train Operations PTC and CBTC

2. Train Control Basic Objectives
Efficiently transport passengers / freight from point A to point B enforcing :
Safety (Safety management)
Train schedules (Traffic management)
whatever the conditions:
Traffic density
Perturbations and failures

3. Why is there a need for train control
Environmental conditions, the mass of the train, and increasing speeds make it more and more difficult to operate safely without the assistance of technology.
Braking distance:
If a car can stop in 75m (dry weather) at 90kph,
a high speed train like the ALSTOM TGV will take 3200m at 300kph…

4. Train Control Signaling
Signaling is fail-safe:
“A fail-safe device is one that, in the event of failure, responds in a way that will cause no harm to other devices or danger to personnel”
Safety is ensured but there is a compromise between:
System “fail-safe” capability
Operating procedures (especially in case of signaling override and manual operation)
Safety measures are usually detrimental to traffic performances, and must be balanced against system reliability and availability.

5. Why Communications Based Train Control (CBTC) and Positive Train Control (PTC)?
Traditional systems in North America have been based on block signaling systems designed years ago
Technology for ETCS (European Train Control System functionally similar to PTC) has been available since the 1990’s in Europe
CBTC Technology was first deployed in Asia in the early 2000’s
Equivalent or better safety
Improved performance
Increased reliability
Higher system throughput & capacity
Improved schedule adherence & reduced variability in system performance
CBTC and PTC systems can offer improvements over block signaling:

6. Line capacity and Safe Braking Distance
Line capacity is the maximum number of trains that can be transported on a line past a fixed point during a set time period.
A signaling system influences capacity by regulating
Dwell time in stations
Minimum train separation required for safety
The minimum train separation is dictated by the safe braking distance of a train
e.g. the distance needed to safely stop prior to a safety hazard
Rolling stock acceleration and braking performance
Maximum authorized train speed
Train detection granularity
Driver reaction time
Safe braking distance

7. Block Signaling
Block Signaling without Automatic Train Protection (ATP)
Movement authorities communicated via signals to driver
Subject to human error / variability
Safe breaking distances designed to worst case scenario not current conditions
Block Signaling with cab signal and ATP
Movement authorities communicated via frequency pulse modulated signals through track circuit blocks
Fail-safe, onboard computers stop train within safety zone
Safe distance between two trains will be the worst case braking distance based speed
Code 40/00 mph
00/00
Speed Code transmission
Braking speed curve
Track Circuit
Stopping point
Code O mph
SPEED CODE

8. Distance to Go and Positive Train Control
Movement authorities communicated based on track conditions ahead and civil speed restrictions
Fail-safe
Permits precision stopping
Eliminates overlap block behind each train
Positive Train Control
Mandated by Law to reliably and functionally prevent:
Train-to-train collisions
Over speed derailments, including enforcement of:
Civil engineering speed restrictions, slow orders, speed restrictions over switches
Incursions into established work zone limits without appropriate authority
The movement of a train through a main line switch in the improper position
Target speed and distance transmission
Stopping point
60 mph
Distance to Go braking speed curve
Track Circuit
Reference: United States of America. Federal Railway Administration. January 5, U.S. Code Title 49: Transportation. Subpart I—Positive Train Control Systems

9. ACSES – PTC on the North East Corridor
ACSES - Advanced Civil Speed Enforcement System
Enforces stops, permanent and temporary speed limits.
Uses braking profiles for warning and enforcement
Receives intermittent line data from transponders
Radio used for dynamic wayside system status updates
ACSES on the North East Corridor is currently applied as an overlay to a block signaling system with cab signaled speed codes
Train detection (track occupancy logic)
Interlocking logic
Broken rail detection
Onboard enforcement of “signal” speed.
2008 after FRA Requires PTC, then Defines ACSES with ATC as PTC:

10. Positive Train Control
Transponders
Communications Based (220Mhz TDMA Radio)
Onboard Controller
Central Safety Server
Wayside Interface Units
Interlocking (external system)

11. Architecture Overview
ACSES:
Onboard receives precise location data and civil speed from transponders.
Wayside Interface Units and Safety Server send interlocking status to Onboard via data radio
Onboard enforces limits and braking profile
Dispatchers may enter specific speed restrictions

12. Transponder Transmission Subsystem
Civil Speed Restriction Data
Positive Train Stop Target
Location Data
Address of wayside equipment

13. Train to Wayside Communication

14. Vital Safety TSR Server to Manage Temporary Speed Restriction Data:
TSR – Train Speed Restriction

15. PTC Interoperability Issues
High need for interoperability between railroads which operate on territories with diverse PTC solutions

16. ACSES Technical Challenges on NEC
Implemented as a mandated safety system, future system optimizations?
Ongoing implementation of new radio band (900 Mhz to 220 MHz) and communication system
Evolving the system to incorporate new products and advancing technologies

17. From Block Signaling to CBTC Moving Block
Code 40/00 mph
00/00
Speed Code transmission
Braking speed curve
Track Circuit
Stopping point
Code O mph
SPEED CODE
DISTANCE TO GO
Target speed and distance transmission
Stopping point
60 mph
Distance to Go braking speed curve
Track Circuit
Gain
CBTC MOVING BLOCK
Moving Block braking speed curve
Movement Authority
Stopping point
80 mph
Protection Envelope
Additional Gain

18. Communication Based Train Control
Per IEEE: System shall provide
high-resolution train location determination, independent of track circuits
continuous, high-capacity, bidirectional train-to-wayside data communications
Automatic Train Protection (ATP) functions shall provide fail-safe protection against
Collisions, excessive speed, and other hazardous conditions
Automatic Train Operation (ATO) functions shall control basic operations within the protection limits imposed by ATP.
Movement Authority precision is increased by absolute train detection envelope
Safe braking distance is based on current train speed and location
CBTC MOVING BLOCK
Moving Block braking speed curve
Movement Authority
Stopping point
80 mph
Protection Envelope
Reference: IEEE Standard for Communications- Based Train Control (CBTC) Performance and Functional Requirements. IEEE Std , Page 1-28, 2005

20. A leader’s experience in radio CBTC :
ALSTOM URBALISTM – More than 25% of radio based CBTC deployments worldwide
A leader’s experience in radio CBTC :
Today, Operators trust URBALIS radio CBTC for 49 metro lines spanning driverless or manned systems, new lines or signaling renovation.

21. Automatic Train Protection – ATP
Maximum speed
Warning curve
Emergency Brake curve
120 km/h
Train Speed
(Manual Driving)
0 km/h
ATP = Supervision of Train Speed
If Train Speed
then Emergency Brake = ON
Else If Train Speed
then Warning Sound = ON
End
>Emergency Brake Speed,
> Warning Speed

22. Automatic Train Operation – ATO
Maximum speed
Warning curve
Emergency Brake curve
120 km/h
Train Speed
(Auto Driving)
0 km/h
ATO = Drives the Train
Traction and Braking of the train is
not managed by the driver, but by the ATO train equipment (Automatic Pilot)
ATO: reduces system reliability while allowing for power consumption optimization

23. Communication Based Train Control
Transponders
Communications Based (2.4, 5.8, 4.9 Ghz)
Onboard Controller
Centralized Zone Controller
Wayside Interlocking Control
Centralized Interlocking processor

24. CBTC General Architecture
ATS & SCADA
PIS & Security
ATC Zone Controller
Interlocking
Controller
Maintenance
DCS – GIGABIT NETWORKS
RADIOS
ATC Onboard Controller
PIS & Security
Interlocking I/O
Station
PIS & Security
ATS: Automatic Train Supervision
PIS: Passenger Information System
SCADA: Supervisory Control And Data Acquisition
ATC: Automatic Train Control

25. Zone Controller Moving Block Operation
Direction of traffic
Movement Authority
Train speed
Automatic protection
Automatic protection A B
Braking curve
ATC Zone Controller
Movement Authority
Location
Train Y …
Train B
Train A
Train X
The Zone Controller calculates Movement Authority based on train location and track database and transmits it to the trains
Onboard controller calculates braking curve and precise location
Trackside beacons contain static location information
In between beacons odometers and high performance slip/slide algorithms are used to calculate location

26. Interlocking: the logic and the track product information
Signal
Switch Machine
Interlocking
Controller
Conditions “out”
switch machine move
signal changes
Track Circuits
Interlocking I/O
Interlocking (Logic)
Conditions “IN”
track circuit occupancy
switch position

27. Control Center for decision support
ATS & SCADA
PIS & Security
Passenger information
Energy, Ventilation, Ancillaries
Security (CCTV,…)
Signalling
Train interface
Mass transit
Suburban

28. Security and Information
ATS & SCADA
PIS & Security
Security and Information
Integrated Security and Passenger Information Center
Visual travel information or emergency messages through displays
Audio & visual information or emergency messages through WiFi communication
People and assets protection through intrusion detection & access control
Event detection, monitoring through video surveillance
Fire Detection
Audio travel information or emergency messages through public address
Emergency call point/intercom
Audio & visual information or emergency messages through kiosk

29. Security and Information – Trainborne
PIS & Security
Audio Announcement
Video Surveillance
Passenger Information
Passenger Emergency Intercom
Infotainment/Advertisement
Internet

30. Data Communication System Complete redundancy for robust availability
ATC Zone Controller
Interlocking
Controller
ATS & SCADA
PIS & Security
Switch Router
Backbone
Redundant Backbone Transmission Network
Station 1
Station 2
Redundant Access Point
Optical
fiber
400m to 1600m (*) AP AP AP AP AP AP AP AP AP
Double Radio Cell
Station
Double Radio Cell
Double Radio cell

31. Innovation in CBTC: Increasing the simplicity of the system through train-oriented architectures
“Wayside-centric” CBTC system
“Train-centric” CBTC system
ATS
ATS
Route request
Train movement
Train movement
Location
Object Controller
Interlocking
Block status, overlap release…
Zone Controller
Train
Track resource request / release
Location EoA
Train
Infrastructure Controller
Several information paths and models to be reconciled
One consistent information path
No need to synchronize Interlocking and ATC
Design can be focused on headway, flexible operation, and robustness performance.

32. System Optimization From System Theory
“Wayside-centric” CBTC system
“Train-centric” CBTC system
Location report
& commitment
Location request MA MA
Following Vehicle
Preceding Vehicle
Following Vehicle
Preceding Vehicle
Train-to-Train communication
End of Authority
Location report
ATC Zone Controller
From System Theory
A technical system throughout its life tends to become more reliable, simple, and effective moving towards a more Ideal state:
Transfer functions to the working element which produces the final action
Cyclic communication
with ATC Zone Controller

33. Conclusions
Advanced train control design and deployment requires a multidiscipline effort to successfully balance safety, performance, and system reliability.
The increasing complexity of train control systems requires an engineering community that can create holistic solutions that match the magnitude of the challenges presented by the transportation industry.
Transportation solutions are a means of improving the quality of life of people living in high density urban centers.

34. THANK YOU

35. Nicholas Columbare Solution Director Strategy and Solution Portfolio
ALSTOM
1025 John Street
West Henrietta, N.Y., 14586