Technical Note - TN 026: 2016
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Technical Note - TN 026: 2016
Issued date:
15 April 2016
Effective date:
15 April 2016
Subject:
Withdrawal of EGG 1541 Design Guideline for
Supervised Locations
This technical note is issued by the Asset Standards Authority (ASA) as a notification to remove
from use RailCorp standard EGG 1541 Design Guideline for Supervised Locations, Version 1.1.
This technical note advises that the published standard EGG 1541 is withdrawn.
Design requirements associated with supervised locations are now captured as part of the
automatic train protection (ATP) project and the System Integrator's processes and specifications.
Refer to the advanced train control migration system (AMS) project for details.
Authorisation:
Technical content
prepared by
Checked and
approved by
Interdisciplinary
coordination
checked by
Authorised for
release
Name
Daniel Oakes
Peter McGregor
John Paff
Graham Bradshaw
Position
Principal Engineer
Technical Standards
Lead Signals and
Control Systems
Engineer
A/Chief Engineer
Director
Network Standards
and Services
Signature
Date
© State of NSW through Transport for NSW
Page 1 of 1
Withdrawn under TN 026: 2016
Engineering Guideline
Signals
EGG 1541
DESIGN GUIDELINE FOR
SUPERVISED LOCATIONS
Version 1.1
Issued 27 September 2012
Owner:
Chief Engineer, Signals and Control Systems
Approved
by:
Warwick Allison
Chief Engineer
Signals and Control Systems
Authorised
by:
Geoff Yarrow
Principle Engineer
Signalling Principles & Design
Technology
Disclaimer
This document was prepared for use on the RailCorp Network only.
RailCorp makes no warranties, express or implied, that compliance with the contents of this document shall be
sufficient to ensure safe systems or work or operation. It is the document user’s sole responsibility to ensure that the
copy of the document it is viewing is the current version of the document as in use by RailCorp.
RailCorp accepts no liability whatsoever in relation to the use of this document by any party, and RailCorp excludes
any liability which arises in any manner by the use of this document.
Copyright
The information in this document is protected by Copyright and no part of this document may be reproduced, altered,
stored or transmitted by any person without the prior consent of RailCorp.
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Engineering Guideline
Design
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Design Guideline for Supervised Locations
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Document control
Version
1.0
1.1
Date
30 July 2012
27 September 2012
Summary of change
New document. First Issue
Figure 15 update; Catch Point information added; Table 1
updated
Summary of changes from previous version
Summary of change
Figure 15 updated
Catch Point information updated. Addition of Figure 12/Figure 13 and associated
details.
Transcription in ATP Data table updated.
Figure 10 and details included.
© RailCorp
Issued 27 September 2012
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Section
5.2.4
5.1.7
6
5.1.5
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Design Guideline for Supervised Locations
EGG 1541
Contents
1
Background .............................................................................................................................4
2
Purpose ....................................................................................................................................4
3
References...............................................................................................................................4
4
4.1
4.2
4.3
Concept ....................................................................................................................................4
ATP Overlap..............................................................................................................................5
Danger Point .............................................................................................................................6
Shunt Routes ............................................................................................................................6
5
5.1
Specific Applications..............................................................................................................6
ATP Overlap..............................................................................................................................7
5.1.1
Conditional/Low Speed Overlap and Full Overlap ....................................................7
5.1.2
Swinging Overlap.......................................................................................................7
5.1.3
Multiple Routes ..........................................................................................................8
5.1.4
Level Crossing ...........................................................................................................8
5.1.5
Buffer Stop.................................................................................................................9
5.1.6
Unwired Track..........................................................................................................10
5.1.7
Catch Points ............................................................................................................11
5.1.7.1 Trailing Points (Converging Tracks).........................................................11
5.1.7.2 Straight Track with Catch Points ..............................................................11
Danger Point ...........................................................................................................................13
5.2.1
Facing Points ...........................................................................................................13
5.2.2
Trailing Points (parallel tracks) ................................................................................13
5.2.3
Opposing Routes .....................................................................................................14
5.2.4
Multiple Danger Points.............................................................................................14
5.2
6
Transcription in ATP Data ....................................................................................................15
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RailCorp Engineering Guideline — Signals — Design
Design Guideline for Supervised Locations
1
2
3
4
EGG 1541
Background
ATP does not absolutely prevent trains passing signals at Stop, due to limited accuracy of
odometry, and (in Level 1) the need for a train to move right up to the signal to get
information updates. For this reason a Supervised Location is normally used, being a
point some distance beyond the End of Authority, within which the train should not be
exposed to risk of collision if it does pass the signal at Stop. This is similar to the overlap
used in conventional signalling.
ATP calculates braking to the supervised location using the emergency braking
parameters programmed in the onboard and assuming the odometry is at the worst-case
limit of accuracy. It is important to understand however that when a fixed release speed is
used, it may be possible for trains to pass the supervised location, albeit at less than the
nominated release speed.
Purpose
This purpose of the design guideline is to provide guidance for signal designers when
identifying supervised locations on signalling plans, in particular ATP overlaps and
danger points.
This guideline identifies examples and scenarios from the current RailCorp network, and
how the overlap and danger point will be determined.
References
The following guideline should be read in conjunction with the following documentation:
•
Signal Design Principle – ESG 100.31
•
RailCorp ETCS Signalling and Operating Requirements
Concept
There are two types of Supervised Locations:
a) the ATP overlap, &
b) the Danger Point
The Supervised Location is that point which the train is targeting as the furthest point
ahead beyond which the train must not pass. It is usually past the EOA. The Supervised
Location changes from the overlap while the train is approaching, to the Danger point
after the train has stopped at the EOA.
The train is considered to have stopped at the EOA if it has:
1. Timed out on a route locking release timer on the signals berth track circuit (or the
virtual representation of this onboard), or;
2. The train actually comes to a stand within the timing area.
ATP Overlap
An ATP overlap acts the same as an ordinary signalled overlap. It is a safety margin past
the End of Authority.
When a movement authority is provided to a train approaching the EOA, it has a release
speed which is calculated on board to be suitable for the emergency braking distance
provided by the overlap.
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Design Guideline for Supervised Locations
4.1
EGG 1541
Similar to the time release of signalled route locking, when the train enters the timing
track circuit, a timer commences that when it expires, or the train becomes stationary
within the timing area, the overlap expires and the release speed is reduced.
Due to the safety-critical nature of the release, the onboard determines that it has entered
the timing distance based on the maximum front end, i.e. half the confidence interval
ahead of the estimated position. This combined with the immediate release when the
train stops within the timing distance, means that even if the timing start location is at the
End of Authority and the timer is set to be infinite, a train stopping close to the signal
would release the overlap because the maximum safe front end would be beyond the
timing start location. For this reason, where there is only one supervised location
applicable, it shall be coded in the ATP data as the Danger Point.
Danger Point
When a train is at a stand at a stop signal, and the overlap has timed out, conflicting
routes may be set ahead of it. If the train proceeded against the signal, the closest point
where it would potentially come into conflict is the Danger Point.
Where the overlap is plain track, and no closer conflict point exists, the Danger Point is to
be coded as the Overlap point (i.e. ATP records the DP).
If no Danger Point is defined, then the EOA becomes the Supervised Location. This will
make it difficult for a train to then move up to a signal to collect a new movement
authority.
ATP Overlap
ATP can use only one overlap, so where multiple overlaps exist (e.g. through facing
points, or conditional and full overlaps) the shortest overlap distance shall be used.
Where the full overlap is the Supervised Location past an End of Authority, such as an
automatic signal, the full overlap will then be classified as the danger point during the
ETCS data preparation.
Figure 1 : ATP Overlap
For an overlap immediately past a controlled signal only where the existing overlap is
greater than 500m, the ATP overlap (and distance) will be marked on the signalling plan
at a location 500m beyond the End of Authority as shown. If the overlap exists in the
down direction, it shall be noted above the running track on the signalling plan. Should it
exist in the up direction, it shall be noted below the running track.
This restriction does not apply to Starting signals or Home/Starting signals where their
overlap is beyond the next automatic signal, but it does apply to the preceding signals’
overlap at the Home or Home/Starting signal.
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Design Guideline for Supervised Locations
4.2
4.3
5
EGG 1541
Danger Point
Notwithstanding the need to code an Overlap as a Danger Point where the signalled
overlap is not time limited, the Danger Point shall be determined as a safe point before
the first potential conflict beyond the End of Authority. Where a Danger Point is to protect
a convergence (points or diamond crossing), the danger point shall be determined as the
surveyed clearance point. Where the clearance point is not specified, the danger point
shall be determined as 3 metres before the location at which the gauge face of the rails
are 2170mm apart.
Unlike conventional signalling overlaps, the Danger Point is referenced from the
immediate signal at stop, not the signal issuing the Movement Authority.
Shunt Routes
For shunt routes, the supervised location will be defined as the End of Authority and a
fixed release speed will be set at 25km/h.
Specific Applications
Route Movement Authority
EOA
NB: Can
also be
Danger
Point if no
crossover
ATP Overlap (500m)
Overlap
ATP Danger Point (200m)
Danger Point
101
103
101AT
101BT
103AT
103BT
Clearance
Point
103CT
101,
ATP 101 (500m)
Figure 2 : Limits of Supervised Locations
The definition of ATP Overlap and Danger Points is outlined (diagrammatically) above.
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RailCorp Engineering Guideline — Signals — Design
Design Guideline for Supervised Locations
5.1
5.1.1
5.1.2
EGG 1541
ATP Overlap
On signalling plans, the distance from the End of Authority to the end of the Overlap shall
be specified along with identification of the signal route for which the overlap is
applicable.
For each overlap, the applicable route shall be specified (M), (M)A, (M)B, etc (Shunt
overlaps not considered).
Following a geographical survey of the infrastructure, the ATP overlap distance shall be
updated to reflect the accurate measurement recorded on site.
For correct symbology of the ATP overlaps, refer to TMD0001 CAD Manual.
Conditional/Low Speed Overlap and Full Overlap
Figure 3 :Conditional/Low Speed Overlap and Full Overlap
101 signal route full and conditional overlaps are shown. ATP uses the shortest overlap
available as the ATP overlap: ATP 101(30m).
Swinging Overlap
Figure 4 : Swinging Overlap
Existing signalling arrangements specify two possible overlaps for 101 signal; through
facing points normal and reverse. ATP will use the shortest signal overlap past the End
of Authority as the supervised location.
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Design Guideline for Supervised Locations
5.1.3
5.1.4
EGG 1541
Multiple Routes
Figure 5 Multiple Routes
Multiple routes from 101 to three alternate End of Authorities, as shown. Each signalled
route ATP overlap is specified.
Level Crossing
Figure 6 : Level Crossing with active protection
Level crossing with active protection shown. A movement authority can be granted to a
signal which qualifies the crossing while at stop (103 signal) with the crossing not
operating. Under this condition, the ATP emergency brake supervision of an approaching
train will be maintained up to the nearest edge of the crossing (supervised location).
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Design Guideline for Supervised Locations
5.1.5
EGG 1541
Figure 7 : Level Crossing with Automatic Signals – no protection
Where the signal is an automatic signal located on the approach to the level crossing and
the signal overlap extends over the level crossing, the supervised location will be the
signal route overlap. This is because the level crossing will always operate on train
approach whether the signal is clear or at stop.
Buffer Stop
Where trains need to closely approach buffer stops in regular service (e.g. terminal
platforms), the conservative estimation used for emergency brake parameters and the
limitations of odometer accuracy would force trains to approach very slowly. To minimise
the operational impact (i.e. forcing the driver to approach the platform at a lower speed
than usual) while still mitigating risk of buffer stop collision, a virtual supervised location
shall be used 40m beyond the buffer stop, and a low fixed release speed will be sent.
End of Authority
101
103
101 AT
Unique SVL:
ATP 103 (40m)
103 AT
Movement Authority
Terminal Platform
Virtual Supervised
Location
Figure 8 : Virtual Supervised Location beyond Buffer Stop
Where there is an overrun distance between the operational stopping location and the
buffer stop such that the supervised location can be located before the buffer stop, then
the buffer stop may be used as the supervised location.
Figure 9 : Supervised Location at Buffer Stop
Buffer stops located on lines other than at terminal platforms shall have the unique
supervised location positioned at the End of Authority, and a low release speed sent.
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RailCorp Engineering Guideline — Signals — Design
Design Guideline for Supervised Locations
5.1.6
EGG 1541
Figure 10 : Supervised Location at Buffer Stop – non-terminal platform
Unwired Track
For a Movement Authority granted from 101, the last limit of signalling authority (shunting
limit) shall be treated as the Unique Supervised Location.
For a Movement Authority granted from 103, the last limit of signalling authority (shunting
limit) shall be treated as both the End of Authority and the Unique Supervised Location.
The ATP Overlap for any previous End of Authority shall not be beyond this location.
End of Authority (101)
101
© RailCorp
Issued 27 September 2012
103
Shunting Limit
101AT
Movement Authority
‘Electric Trains Stop’
Unwired Section
103AT
Movement Authority
ATP Overlap
101
Unique SVL - Overlap
ATP 101 (200m)
Figure 11 : Unwired Track
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Design Guideline for Supervised Locations
5.1.7
Catch Points
5.1.7.1
Trailing Points (Converging Tracks)
5.1.7.2
EGG 1541
Figure 12 : Trailing Points (converging tracks) and Catch Points
Where two tracks converge into one (and catch points are provided on the converging
line), the Unique Supervised Location shall be the surveyed clearance point* (or 3m
before the location at which the gauge face of the closest rails are 2170mm apart if the
clearance point is not surveyed). The catch points themselves are not specifically treated
as the danger point, as the unique supervised location will never be reduced after the
operation of the route holding release timer.
*Note – generally, the clearance point and the start of the throw off rail of the catch points
are aligned - as per Figure 14.
Straight Track with Catch Points
Where catch points are provided with straight track and the throw off rail is closer to the
End of Authority than the Clearance Point, the start of the throw off rail is considered to
be the unique Supervised Location.
© RailCorp
Issued 27 September 2012
Figure 13 : Straight Track with Catch Points
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Design Guideline for Supervised Locations
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Figure 14 : Catch Points Supervised Location
Note: The unique Supervised Location for catch points is depicted as the switch blade on
signalling plans. The actual location of the unique Supervised Location on the track shall
be considered to be the start of the throw off rail, as per Figure 14.
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RailCorp Engineering Guideline — Signals — Design
Design Guideline for Supervised Locations
5.2
Danger Point
5.2.1
Facing Points
5.2.2
EGG 1541
Figure 15 : Facing Points
With a train signalled from 101 to 103 with one of the overlaps occupied, the points are
locked in the unoccupied overlap position (overlap maintenance applied). After the train
times out on the berth track to 103, the points are free to swing to the occupied overlap.
The danger point is defined as the closest end of a track circuit which could be occupied
while still allowing the points to swing, i.e. first track circuit beyond the points’ ‘dead’
locking.
Trailing Points (parallel tracks)
End of
Authority
101
ATP Overlap
ATP DP 103 (20m)
103
101AT
103AT
103BT
Movement Authority
103CT
101,
ATP 101 (150m)
Figure 16 : Trailing Points (Parallel Tracks)
Where trailing points (or a diamond crossing) fall within the overlap, the Danger Point
shall be the clearance point. Where the clearance point is not clearly defined, the Danger
Point shall be 3m before the location at which the gauge face of the closest rails are
2170mm apart.
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Design Guideline for Supervised Locations
5.2.3
5.2.4
EGG 1541
Opposing Routes
Figure 17 : Opposing Routes
In the absence of any other hazards, there is no need to specify a danger point where
opposing routes have overlaps that coincide; i.e. only the Overlap and not the Danger
Point shall be specified for respective Movement Authorities.
Multiple Danger Points
Figure 18 : Multiple Routes
Where multiple points configurations exist, all conflicting movements for each respective
route must be considered when determining the closest conflicting point past the End of
Authority as the Danger Point.
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Design Guideline for Supervised Locations
6
Fig.
EGG 1541
Transcription in ATP Data
Route
EOA
Q_DANGERPOINT
D_DP
V_RELEASEDP
Q_OVERLAP
D_OL
V_RELEASEOL
1
C1
C3
1
500
126
0
-
-
2
101
103
1
200
126
1
500
126
3
101
103
1
30
15km/h
0
-
-
5
101(M)A
103
1
250
126
0
-
-
5
101(M)B
105
1
250
126
0
-
-
5
101(M)C
107
1
300
126
0
-
-
6
101
103
1
180
126
0
-
-
8
103
BF
1
40
10 km/h
0
-
-
10
103(S)
L.O.S
1
0
15km/h
0
-
-
11
101
105
1
30
15km/h
0
-
-
11
103
107
1
30
15km/h
1
120
126
12
103
107
1
20
15km/h
0
-
-
15
101
103
1
20
15km/h
1
150
126
16
110
108
1
300
126
0
-
-
16
103
107
1
150
126
0
-
-
Table 1 : ATP data transcription of examples
Where:
EOA
End of Authority
Q_DANGERPOINT
Qualifier for Danger Point (0 = No Danger Point, 1 = Danger
Point information to follow)
D_DP
Distance from End of Authority to Danger Point
V_RELEASEDP
Release speed associated with Danger Point (126 = Compute
onboard or 15km/h)
Q_OVERLAP
Qualifier for Overlap (0 = No Danger Point, 1 – Danger Point
information to follow)
D_OL
Distance from the End of Authority to the end of the Overlap
V_RELEASEOL
Release speed associated with the Overlap (126 = Compute
onboard or 15km/h)
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