1. Train Collision Avoidance System (TCAS)
KERNEX MICROSYSTEMS
A Presentation on
Train Collision Avoidance System (TCAS)

2. TCAS Project
TCAS Development project was awarded to 3 Companies, as below:
Package A- 140 KM awarded to Medha
Package B- 70 KM awarded to Kernex
Package C- 40 Km awarded to HBL

3. TCAS Project - location map

4. Package B (Kernex Scope) - location map

5. Main Objectives of TCAS
Safety
Prevention of SPAD
Control of Speed at PSR/TSR
Facility of SOS
Prevention of Collision during NI Working
Operational
Simple Operation by Loco Pilot
Continuous Update to ensure no Loss of Line Capacity
Limited Trackside Equipment

6. Major Sub-Units of TCAS
Station Units located in stations
Loco Units located in locomotives
IBS/LC Units located in block sections
Centralized monitoring system
Test benches at Loco Sheds

7. TCAS Block Diagram

8. Architecture & Components
TCAS
Architecture & Components

9. Typical Deployment Plan
(GPS)
Radio Communication
Station TCAS
Station TCAS
Loco 1
Loco 3
Loco 2
RFID

10. Loco TCAS - Schematic

11. Loco TCAS major Sub-systems
Dual Microprocessor based control system, along with dual redundant radio modems, RF Tag Readers and GPS Receivers
Interface to the existing speedometer
Event Logging sub-system along with blue-tooth data uploading/down loading facility and redundant GSM I/F.
Two Loco pilot Operation cum indication panel (LPOCIP) – for Loco pilot and Asst. Loco pilot
Braking interface unit (BIU)
Dual Isolated Power Supply unit

12. Loco TCAS Architecture

13. Loco TCAS – Architectural Features
Two redundant Microcontrollers (MIE 1 & MIE 2) working in “2 out of 2” mode to achieve high level of safety.
All modules are connected through redundant CANBUS.
Two redundant Microcontrollers (MIE 3 & MIE 4) as communication processors.
Two redundant Microcontrollers for peripheral interface.
Separate Event logger for major events logging and storing for 90 days.
Two UHF full-duplex Radio Communication Equipment with hot standby and associated antennae:
Frequency for Transmission by Loco : MHz
Frequency for Reception by Loco : MHz
Transmission by Loco for emergency (SOS) Communication : 466.8MHz

14. Loco TCAS – Architectural Features ( Contd..)
Dual Redundant GPS units are interfaced with Loco TCAS to get synchronization for TDMA as well as to act as standby when speedometer fails.
Radio Antennae & GPS receiver antennae are permanently fixed on the rooftop of the locomotive and connected to the Loco Unit through RF cables.
Dual Redundant RF-ID readers for finding Track Identification Number (TIN) and Absolute location.
Dual Redundant GSM/GPRS modems for health check and transfer of failures to CMS.
Bluetooth device for data up-loading and down loading.
USB port for Event down loading.
Loco Unit interfaced externally with Braking Interface Unit (BIU).
Multi level Braking system, with the help of a proportional valve.

15. Loco Pilot Operation cum Indication Panel
Two LP-OCIPs (Operation cum Indication Panel) provided for Loco pilot and Asst. pilot interaction with TCAS.
Functions performed:
Speed indication in analog and digital forms
Display of immediate signal aspect
Target distance and movement authority in meters
Generation of SOS
Selection of Leading/ Non leading of loco
Light engine/ Formation selection
Display of system health

16. Loco Pilot Operation cum Indication Panel

17. Breaking Interface Unit (BIU )
Based on Proportionate Valve – Brake pipe pressure will be proportional to the input voltage
Separate Light engine brake
Separate Dedicated valve for emergency brake
Does not interfere with the brake action of the Loco Pilot
No continuous leakage of air after achieving the required pressure.

18. RF Tag placement in Station
To be provided by Ajaiah

19. Station TCAS major Sub-systems
Dual Microprocessor based control system, along with dual redundant radio modems and GPS Receivers
Event Logging System along with blue-tooth data uploading /down loading facility and redundant GSM Interface and OFC Interface.
Station Master operation cum indication panel
Station yard layout and status panel (21”)
Dual Redundant Power Supply unit
Battery and Battery charger
30 meter Tower for radio modem.

20. Station TCAS Architecture

21. Station TCAS Architectural Features
Two Microcontrollers (MIE 1 & MIE 2) working in “2 out of 2” mode to achieve safety of desired functionality.
All modules are connected through redundant CANBUS.
Two redundant Microcontroller (MIE 3 & MIE 4) working on for radio communication and display.
Event logger for major event logging and storage for 30 days
Two UHF full-duplex Radio Communication Equipment with hot standby and associated antennae
Frequency of Transmission by Station : MHz
Frequency of Reception by Station: MHz
Two GPS units are interfaced with Station TCAS
Radio Antennae & GPS receiver antennae are permanently fixed on the preinstalled 30 mtr towers.
Two GSM/GPRS modems for transfer of failures to CMS.

22. Station TCAS Architectural Features ( Contd..)
Station-OCIP (Operation cum Indication Panel) provided for
station master.
Existing fail safe signal, point status relay interface contact
input reading.
21’’ LCD monitor for yard display.
Bluetooth device for data Transfer.
Battery with battery charger cum power supply to provide
up to 24 hrs.

23. IBS/LC TCAS
Intermittent block Station/ Level crossing gate TCAS is similar to Station TCAS Unit, but with less no. of Inputs / outputs.
No user interface
Acts like a base station

24. Centralized Management System
GSM
Network
Railnet
Loco 1
Web
Reports
Central
Management
System
Loco 2
Loco 3
Web
Reports
LAN Network
Station A
Station B
Station C
Station N

25. Station/IBS/LC TCAS - Schematic

26. Trackside RFID Tags RFID Tags Provided at
Start/End of TCAS Territory
One Kilometer on Straight Track
At Turnouts to detect diversions and Infringements
Block Entry – foot of Last Stop Signal
Station Entry – at the end of the Block Overlap at the Station
Foot of Signal
Each Location with Pair of Tags for Redundancy
Rigid Fixture with Clamps on Sleepers

27. TCAS
System Functions

28. ATP Functions In-Cab Signaling Detection and Prevention of SPAD
Display of Distance of Signal and Movement Authority
Loop Line Speed Control
Speed Control at PSR/TSR

29. Collision Prevention Scenarios
Prevention of Head-On Collision
Prevention of Rear-End Collision
Prevention of Collision due to Unusual Stoppage in Block Section
Detection of Train Parting with External Input
Manual SOS Generation Feature in Station TCAS
Manual SOS Generation Feature in Loco TCAS
Detection of Roll back

30. Supporting Functions Full Duplex Radio Communication
Location with RFID and Existing Tachometer
Automatic and Manual Brake Test
No Database in Locomotive TCAS Unit
Automatic Train Length Measurement Feature
Station to Station Communication for Additional Layer Block Protection

31. Modes of Operations Normal Mode
Controlled Mode (when any vital system fails)
Restricted Mode (15 Kmph operation)
Staff Responsible mode (Manual mode)
Coupled / banking operation
Trip and Post Trip Modes
On-Sight Mode
Reverse Mode (to move in reverse direction)
Shunting mode

32. Features of TCAS Full Duplex Radio Communication
Location determination with RFID and existing Tachometer
Automatic and Manual Brake Test
No Database in Locomotive TCAS Unit ; hence operation, handling of yard layout changes will be easy.
Automatic Train Length Measurement Feature
Station to Station Communication for Block Protection (as additional layer)
Time synchronization of complete network through GPS

33. Features of TCAS ( Contd..)
Handling of New Train Formation
RFID based Track Id & Location Determination
Multi Level Braking Interface
Provision of Controlled Mode (Manual mode) Operation
TDMA based Communication protocol
Startup/Online Diagnostics
Event Logging
Central Monitoring through GSM / GPRS network for maintenance
Data up-loading & down loading through ‘Bluetooth’.

34. Environmental Specifications
Operating Temperature: -10 to +70 deg. C
Relative Humidity : 95% (non-condensing)
Vibration : 3 g for Loco; 2 g for Station & LC
Mechanical Shock : 20 g peak for 11 msec. (non-operating)
Bump : 40 g peak in packed conditions
MTBF (Planned)
- Loco unit: 20,000 hrs
- Station Unit: 60,000 hrs

35. Present Status
Installed Station TCAS in Nawandgi and Kurukunta stations
Installed Loco TCAS in one electric and one diesel loco
KMIL participated in several field trials to study / verify
Radio communication
RFID readers and tags
Inter-operability with other vendors equipment between stations Tandur, Mantatti, Nawandgi and Kurukunta.
Various control logics including SPAD
Prototype testing completed. (Same was used for site trials since Jan 14.)
Independent Safety assessor (ISA) clearance for Hardware design completed.

36. Present Status ( Contd..)
System documents under review by ISA.
Soil test for Tower erection completed.
Approval for Tower locations in stations and LCs from SCR
obtained.
Tower design with CPRI approval completed.
Relay room wiring in Station- approval from SCR obtained.
Unit level manufacturing in progress.
Software documents under review by ISA.
Software Functional logics developed and tested during site
trials.

37. TCAS
Scenarios

38. Detection & Prevention of SPAD
Approaching Signal Aspect is Transmitted by Station TCAS to Loco TCAS
Loco TCAS Displays Signal Aspect on LP-OCIP
In case Driver fails to apply brakes to reduce the speed/stop the train, TCAS Applies brakes to stop the train.
On Change of Signal Aspect to green, brakes will be released

39. In Cab Signaling
Station TCAS gets inputs from Signaling and transmits the same to the approaching Loco TCAS
The Signal Aspect of the next approaching signal is displayed on the LP-OCIP
Movement authority is also displayed along with the signal aspect on the LP-OCIP
On Crossing the Signal, Next Signal Aspect and Movement authority is automatically updated on the LP-OCIP

40. Display of Signal & Movement Authority

41. Loop Line Speed Control
Station TCAS gets inputs from Signaling and transmits the route Information to the approaching Loco TCAS
In case the route is set to Loop Line and the Loco Pilot does not apply brakes to achieve speed limit, Loco TCAS applies brakes to regulate to the Loop Line speed Limit
If Loco Pilot applies brakes, then Loco TCAS will not apply brakes as speed is monitored dynamically

42. Prevention of Head-On Collision
Two trains approach each other in Block section on the same Track is sensed.
Station TCAS Transmits the HOC Condition to both Locos
Both Locos individually deduce HOC Condition based on Emergency Broadcast
Brakes are applied to both the Locos and brought to a stop

43. Prevention of Rear-End Collision
Two trains approach each other in Block section on the same Track is sensed.
Station TCAS Transmits the REC Condition to both Locos
Both Locos individually deduce REC Condition based on Emergency Broadcast
Brakes are applied to the Rear Loco and brought to a stop

44. Unusual Stoppage in Block Section
One Train Stopped in Block Section either due to Derailment or for any other Reason is sensed by Station TCAS
Station TCAS Transmits the Unusual Condition to the other Loco entering the Block Section
Unusual Stoppage Emergency Broadcast also is sensed by the approaching Loco
Brakes are applied to the Approaching Loco and regulates to 15 Km/h
In case there is no obstruction, Loco Pilot can increase the speed after crossing the stopped Train

45. Manual SOS from Station
There is a provision on SM OCIP for generating emergency condition
SM can Press the Manual SOS buttons
All trains within the range of 3000m applies EB and stops
Loco Pilots of the trains can press the Manual Override and pilot the train at 15 Km/h
On Cancellation of Manual SOS in the Source Loco, Speed restriction is removed

46. Manual SOS from Loco
There is a provision on LP OCIP for generating emergency condition
Loco Pilot can Press the Manual SOS buttons
All trains within the range of 3000m applies EB and stops
Loco Pilots of other the trains can press the Manual Override and pilot the train at 15 Km/h
On Cancellation of Manual SOS in the Source Loco, Speed restriction is removed

47. Prevention of Collision due to Train Parting
Using External Sensor for Train Parting, Loco TCAS detects train parting condition
Train Parting Message is sent to the Station TCAS as well as transmitted in the Emergency Communication Slots
Any Loco TCAS approaching the Parted Loco TCAS applies brakes to regulate the speed to 15 km/h
Driver can look out for infringement and can go at full speed on crossing the Parted Train

48. Train Length Calculation
Loco Unit Stores its position and speed in FIFO
Station TCAS transmits the Start marker time stamp T1 to Loco TCAS (in millisecond accuracy)
Station TCAS transmits the End marker time stamp T2 to the Loco TCAS (in millisecond accuracy)
Based on the start and end time and the speed at which Loco is traveling, Loco TCAS calculates the Train Length

49. Train Length Calculation
Event “End“
Event “Start“
Train Length
Event “Start“
Event “End“
Frame #n
Frame #n+1
Frame #n+2
Frame #n+3
Frame #n+4
t (Start)
t (END)

50. Auto Brake Test & Manual Brake Test
When Loco reaches a speed of more than 50 Km/h and is accelerating, Loco TCAS applies NB through Braking Interface Unit (BIU)
Speed is reduced by 20 Km/h
Based on the time taken, Deceleration constant (DC) of the train is calculated and stored for any future brake application.
Default DC is taken as 0.2 m/s2
Calculated DC is extrapolated for application of FSB and EB
Manual Brake Test is applied in Loco sheds to test the functioning of BIU

51. Architectural Features and
TCAS
Architectural Features and
Safety Certification

52. TCAS Architectural Features
Two redundant Microprocessors/controllers (MIE 1 & MIE 2) working in “2 out of 2” mode to achieve safety of desired functionality
Two redundant Microprocessor/controller (MIE 3 & MIE 4) working on for radio communication and display.
Two full-duplex Radio Modems with hot standby and associated antennae
One GPS unit is interfaced with Loco TCAS to get time synchronization for TDMA as well as to act as standby when speedometer fails.
Radio Antennae & GPS receiver antennae are permanently fixed on the rooftop of the locomotive and connected to the Loco TCAS through RF cables.

53. TCAS Architectural Features Contd..
Interfaced with two RF-ID readers for finding Track ID.
Interfaced with two GSM/GPRS modems for transfer of failures to CMS.
Interfaced with two LP-OCIP’s (Operation cum Indication Panel) which are mounted on the Driver’s pedestal for easy access and visibility to the Driver.
Interfaced with Bluetooth device for data Transfer.
Loco TCAS interfaced externally with Automatic Braking Unit (ABU) for Normal Brake, Full Service Brake and Emergency Brake
Interfaced with 2 Field Input Modules (FIM) for Inputs.
Interfaced with 2 Field output Modules (FOM) for outputs.

54. TCAS Architectural Features Contd..
Loco TCAS interfaced with existing odometer’s pulse generator to compute location data.
Loco TCAS also interfaces with Inter-Cock Switch (ICS) to determine coupling / banking mode of train operations
Logging of eventlogs by eventlog module, which can be downloaded through Bluetooth.
1 Battery with battery charger to provide up to 30 min power backup.
2 Hot Standby redundant power supply modules to provide power supply to all the modules of Loco TCAS Unit

55. Safety Certification
Independent Safety Assessor (ISA) done by ERTL, Kolkata
Hardware Design is Verified to provide required Safety
Software Design is Verified to provide required Safety
System is Validated Independently to ensure proper functionality
Design and Safety Documents are Verified to meet required Safety Level
On completion of assessment, Certification is done

56. TCAS
Radio Communication

57. Radio Communication Full Duplex Communication
Stationary Units Transmit on Frequency ‘F1’ and Receive on ‘F2’
Locomotive Units Transmit on Frequency ‘F2’ and Receive on ‘F1’
In Emergency Situations, Loco Units also transmit in ‘F1’ and tune back to ‘F2’ for Listen.
Uses Time Division Multiplexing (TDMA) for Communication

58. Communication Time Frame
Timeslot Position Marker 1 2 3 7 45 46 55 56 66 68 72 75 79 81 86 S1 S4 S5 S6 S7 S8 S9
Tx by Stationary (f1)
1094 Bits ( Repeater/End Cabin)
1094 Bits ( Repeater/End Cabin)
3504 Bits
3504 Bits
3504 Bits
3504 Bits 48
304 96
304 96 96
304 96 96 96 96
496
304
496
304
496
304
496
304
496 48 M1 M5
M39
M40
M44
M45
M53
M54
M62
M63
M71
MTP
M72
M76
2704 Bits
Tx by Train (f2) 48
304 96
304 96
304
304
304 96
304
304 96
304
304 96
304
304 96
304
304
496
496
304
304 48
MR3
MR4
ME3
ME4
Tx by Train
( Addl SOS/ Emergency Tx)
(f1)
304
496
304
496
304
496
304

59. Position Determination
TCAS
Position Determination

60. Position Determination
Loco TCAS is fitted with two RF Readers.
RF Tags are fitted on the sleeper
On Crossing RF Tag, Loco TCAS gets Absolute Position
From tachometer Speed, position is accumulated
GPS is used as fall back, in case of tachometer failure
Tag Crossed + distance traveled is Transmitted to Station TCAS
Station TCAS Calculates position of Train based on Absolute Position of Tag + Distance Traveled

61. THANK YOU Kernex Microsystems (India) Limited
‘THRUSHNA’, PLOT NO 7, A.P.I.I.C LAYOUTS
HI-TECH CITY, MADHAPUR, HYDERABAD –
Tel: , Fax: ;
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