Signalling and OHTE

vs

Track

2

•INTRODUCTION

•Concept of “Track Vacancy Detection”

•Track Circuits

•How they work

•Some problems arising

•Addressing these problems

•Axle Counters

•How they work

•Problems

•New developments

•OHTE

BACK TO THE FUTURE – Biennial

Symposium

3

Track Vacancy Detection Equipment

• Track Circuits

• Axle Counters

Train Authorisation Technology

3 BACK TO THE FUTURE – Biennial

Symposium

4

Track Circuits

Track Vacancy Detection

Train Authorisation Technology

4 BACK TO THE FUTURE – Biennial

Symposium

5

Track Circuits

Basic Principles : Relays

N

a

b

c

a

b

c

Train Authorisation Technology

5 BACK TO THE FUTURE – Biennial

Symposium

6

Track Circuits

i

A

Basic Principles

Train Authorisation Technology

6 BACK TO THE FUTURE – Biennial

Symposium

7

Track Circuits

i

A

Basic Principles

Train Authorisation Technology

7 BACK TO THE FUTURE – Biennial

Symposium

8

Track Circuits

i

A

Basic Principles

Train Authorisation Technology

8 BACK TO THE FUTURE – Biennial

Symposium

9

Track Circuits

• Insulated Rail Joints used in Signal leg

• Traction return leg solid

• Rails insulated from ballast

• Sleeper insulated from rails.

Train Authorisation Technology

9 BACK TO THE FUTURE – Biennial

Symposium

10

Insulating Track Circuits

1 TR 2TR

i1 i2

Insulated Rail Joints

Train Authorisation Technology

10 BACK TO THE FUTURE – Biennial

Symposium

11

Insulated Rail Joints (Block Joint)

Train Authorisation Technology

11 BACK TO THE FUTURE – Biennial

Symposium

12

Train on Track

i

Train Authorisation Technology

12 BACK TO THE FUTURE – Biennial

Symposium

13

Ballast stone & Track Circuits

• Ballast resistance > 2,1 Ohm/km

• Contaminated ballast increases leakage currents

• Ballast MUST not touch rails.

Train Authorisation Technology

13 BACK TO THE FUTURE – Biennial

Symposium

14

TR

i1 i2 i3 i4

iB

Ballast stone & Track Circuits

Train Authorisation Technology

14 BACK TO THE FUTURE – Biennial

Symposium

15

Track Circuit Requirements

• Must shunt with 0,5 Ohm

• Operate safely and reliably

• Should not drop with ballast resistance of 2,1

Ohm/km

• Immune to environmental conditions

• Long as possible

• Cost effective.

Train Authorisation Technology

15 BACK TO THE FUTURE – Biennial

Symposium

16

Types of Track Circuits

• Jointed Track Circuits o Block Joints (Insulated Rail Joint)

required

o One Traction return leg

• Jointless Track Circuits o Simulated Block Joints

o Both rails available for traction return

d.c. (Old)

d.c. a.c.- Immune

a.c. 50 Hz

Jeumont

M.L.TI21

Train Authorisation Technology

16 BACK TO THE FUTURE – Biennial

Symposium

18

a.c. Track circuit

• 50 Hz Power supply

• Diesel and d.c. Traction areas

• No longer Purchased

50 hZ

Train Authorisation Technology

18 BACK TO THE FUTURE – Biennial

Symposium

19

Jeumont Track Circuit

• Specially shaped high voltage pulses

• Special receiver and relay

• Immune to 50 Hz interference

Train Authorisation Technology

19 BACK TO THE FUTURE – Biennial

Symposium

24

Points

TURNOUTS

Train Authorisation Technology

24

Straight

+

-

-

+

-

+

BACK TO THE FUTURE – Biennial

Symposium

25

Track Circuit Failures

Block Joints

Ballast stone

Train Authorisation Technology

25 BACK TO THE FUTURE – Biennial

Symposium

28

Train Detection

• Axle Counters

o Used instead of Track circuits

o Detects Completeness of trains

o Counts Wheels and

o Determines direction

28 BACK TO THE FUTURE – Biennial

Symposium

29

Axle Counters

Axle counter Heads

“Insert” “Insert” Evaluator

Communication Cable

29 BACK TO THE FUTURE – Biennial

Symposium

30

Axle Counter Heads

• Position is Critical

• Replacement requires Adjustments

• Two Frequencies to Heads

• Supervision Frequency

• Heads Detected in Position

• Presence of Wheel Changes Magnetic field &

Phase

• Pulses Correspond to Wheels.

30 BACK TO THE FUTURE – Biennial

Symposium

31

Transmit Heads (SEL)

31 BACK TO THE FUTURE – Biennial

Symposium

32

Receive Heads

32 BACK TO THE FUTURE – Biennial

Symposium

33

Multi Head Axle Counters

Siemens AzSM(350R)

33 BACK TO THE FUTURE – Biennial

Symposium

34

Path of Traction Current

BACK TO THE FUTURE – Biennial

Symposium

35

TRACTION LEAKAGE

CURRENTS

BACK TO THE FUTURE – Biennial

Symposium

36

TR

i1 i2 i3 i4

iB

Train Authorisation Technology

36 BACK TO THE FUTURE – Biennial

Symposium

37

TR

i1 i2 i3 i4

iB

Train Authorisation Technology

37 BACK TO THE FUTURE – Biennial

Symposium

38

Examples of bad maintenance

by OHTE

39

Ballast touching rail and rail

fastenings

BACK TO THE FUTURE – Biennial

Symposium

40

Results of the ballast and earth

returns not according to rules

BACK TO THE FUTURE – Biennial

Symposium

41

How a mast should be

installed

New ballast still

touching the rail

BACK TO THE FUTURE – Biennial

Symposium

BACK TO THE FUTURE – Biennial

Symposium

CONCLUSION