|Category: Technical Papers|
|Technical Papers||Files: 20|
|2017 - March - Moore - Signalling system safety is NOT an absolute|
Trevor Moore Hon FIRSE FIEA Aust
Australian Rail Track Corporation
We often design a signalling system and continue its operation even though there are significant changes in train operating conditions. Do we assume that is still as safe as the day it was commissioned into service?
Some cases are self-evident that safety has changed. If we increase the train speed over a level crossing we know that the approach warnings have to be reviewed and updated. Do we check and update if they have changed the road traffic classification to B double trucks?
When and how should we review the signalling system for safety of operations? What should be the catalyst to undertaking a review? Should this be part of the standard practice for signal engineers managing infrastructure and for signal designers on new works?
|2017 - March - McDonald - Is RAMS all BULL for Electromechanical Equipment?|
Wayne McDonald BE (Elec) FIRSE
Railways are required to operate safely and one of the methods to demonstrate this is type approval of signalling equipment. That approval must include documentation of high RAMS (Reliability, Availability, Maintainability and Safety) when applied in vital and even non-vital applications. Suppliers have provided such values, in some form or another, for electrical, electronic and programmable electronic equipment for many years. The limitations and applicability of these values have not always been well understood and they have often been misapplied. The decisions for product comparison or maintenance plans could therefore be compromised or invalid.
More recently, purchasers, and personnel assessing type approval are demanding values such as SIL (Safety Integrity Level) and MTBF (Mean Time Between Failure) for electromechanical equipment and systems. The standards currently used for programmable electronic systems clearly state that using them to derive values for electromechanical is inappropriate.
This paper delves into the importance of understanding and applying meaningful RAMS values for signalling equipment and addresses the inappropriateness of SIL and MTBF for Electromechanical Equipment. It continues to offer some suggestions for how RAMS can be used for Electromechanical Equipment.
|2017 - March - Leveque - Advanced features over ETCS for suburban railway operation|
Dr Olivier Leveque
Alstom Signalling – Australia New Zealand
The advanced features over ETCS detailed in this paper are Virtual Block Sectioning and scalable Automatic Train Operation. These features can be incrementally implemented to meet the current and future business requirements of a suburban railway operation. A case study is presented to illustrate the performance benefits of a scalable ATO overlaid onto an ETCS solution for a suburban application.
|2017 - March - Gillespie - Are CAD drawings the best way to design signalling systems|
Rob Gillespie NTD Elec Eng.
I&E Systems Pty Ltd
Modern railway signalling systems now incorporate computer-based interlocking, and the wiring is predominantly simple input/output functions, so, is CAD really the best way to design these high integrity systems?
|2017 - March - D'Cruz - Do we have the backbone to support emerging technologies?|
Malcolm D’Cruz M.E. Mechatronics
Public Transport Authority of Western Australia
David Lim MSc. Telecommunication Management
UXC Ltd – A CSC Company
Railways are always increasing the number of network services to cope with emerging technologies. The success of Communication Based Train Control (CBTC) depends on the ability of the backbone communication system to guarantee high bandwidths and reliability. Thus the traditional railway communication network is gradually moving towards a carrier grade network servicing both internal as well as external clients.
The aim of this paper is to show how Software Defined Networks (SDN) adopted by telecom service providers as a common platform for all network services can benefit the railway networking environment to cope with constantly emerging technologies.
|2017 - March - Boshier - Technology based asset management|
Steve Boshier FIRSE, FCILTA
Asset Management is an area that continues to develop through innovation, technical developments and through new ways of looking at whole of life management. In tough economic times, businesses often take short cuts with asset management in a bid to remain profitable. Its usually one of the first areas whose budget gets cut back for a whole range of reasons. Such a decision only provides a short term solution to a problem that ultimately gets worse and comes back to bite even greater.
Technologies such as BIM, Mobility, Analytics, and a suite of ISO standards represents a coming of age for rail systems asset management. They are transforming the rail sector and are helping to drive a long term approach to maintenance with benefits. One that is now allowing staff to do more with less whilst allowing them to improve the asset reliability, availability and system safety.
|2016 - Sept - Cox - Level Crossings, When is enough, enough?|
|2016 - July - Pfister - Swiss Army Knife vs KISS How to optimise a level crossing 1|
Assuming you get the job to implement or update a new level crossing: You will be confronted with lots of stakeholders,
|2016 - July - Macdougall - Headway as Part of the Operating Plan 1|
Signal engineers and train operations staff often misunderstand each other when talking about headway.
When someone in the operations team refers to headway, they actually mean the interval between trains expressed in minutes. They assume that the interval between trains is enough to deliver a reliable on-time service.
Signal engineers however calculate headway as the absolute minimum time between following trains that will allow drivers to retain line speed without having to apply brakes due to passing yellow signals.
The signal design will generally try to space signals so that there is a fairly uniform headway across a section of line. The worst headway on the line sets the "ruling headway" for the line. This is sometimes called the theoretical signalling headway. Trains travelling closer than the ruling headway will meet at least one yellow signal and be forced to apply brakes, and will therefore lose time. This in turn will delay the following train and so on, causing cascading and compounding delays.
Several factors contribute to achieving reliable train frequencies, such as the permitted line speed, driver behaviour, train acceleration & braking rates, train length, signalling principles (such as overlap length), planned station dwell time, and most importantly, passenger behaviour.
This paper provides a brief background on classical headway theory; some insight on how track speed and station dwell time impact on achievable capacity; a case study to demonstrate that terminal stations may pose a greater constraint on capacity than the signalling; and a suggested method to allow quick assessment of achievable capacity on a new line.
|2016 - July - Heibel - CBTC Versus ETCS - Score and Forecast 1|
Modern in-cab signalling can increase capacity beyond the limits of conventional legacy systems and also improve service punctuality. The present market for in-cab signalling is divided in two segments. For mainline railways on a national level, the European Train Control System (ETCS) is preferred by railway operators well beyond the reach of European legislation. For high performance metro-style city railways, Communications Based Train Control (CBTC) is the solution of choice. Both technologies have different purposes and histories and consequentially developed distinct strengths but also weaknesses.
The suburban railway systems in the major Australian cities appear in a transition from a mainline legacy to high capacity metro ambitions. The technology selection between ETCS and CBTC is therefore less straightforward with no clear "right" or "wrong" and examples for either system evolving in Australia. However, operators need to recognise and accept the consequences of selecting either technology.
The paper concludes with an outlook on further development of both technologies, which concentrates on addressing the individual shortcomings while maintaining existing advantages. The evolving subject of "convergence" between ETCS and CBTC will be discussed to assess whether there will be only one "best" signalling technology in the future.
|2016 - July - Green - Re-Engineering Level Crossing Safety 1|
This paper describes components and processes to re-engineering level crossing safety by controlling the movement over level crossings for both road and rail vehicles. This is primarily aimed at highway crossings and in particular remotely located crossings on heavy haulage rail lines.
The rail corridor has always been designated as a permanent way with the train driver as the only stopping control to avoid collisions with obstructions. With the introduction of new technologies and driverless train projects the need to detect obstructions and control the passage of trains across conflict zones such as level crossings has become vital.
These new technologies must be introduced with strict operational guidelines that are fit for purpose. Technology that increases train delays due to false or unreliable alarms is not an acceptable solution.
System components for this design will include
Duplicated Flashing Lights
Duplicated Half Boom Gates
Barrier protection around level crossing equipment locations
CCTV with integrated crossing state logging
Obstruction Detection in the crossing zone
Duplicated Advance Warning Lights
Road Speed Reduction
Full Road Pavement Markings and duplicated road signage
Vital Communications to stop the train
All components play an important role in level crossing protection.
|2016 - July - Burns - Time Based Movement Authorities 1||
Modern communications based signalling places improved signalling functionality on board the train.
This can be used to enforce conventional temporary speed restrictions using location based authorities. With these the train ensures its speed is maintained below the temporary maximum between two defined points.
In a related class are time based authorities. A time based authority commences at a specified time and continue to a specified event (which is not necessarily time based). Two examples are presented.
The first relates to a requirement to restrict passing speeds within a long tunnel to below a specified maximum (as is the case for the Seikan tunnel in northern Japan).
In this case the signalling system is aware of the location and authorized speed of the two passing trains in advance. With this knowledge a passing point can be predicted in terms of location. However, a speed restriction based on this criterion can be shown to be unsound as a provider of safety. Thus a safety benefit is obtained by defining the passing point in terms of time; a time based authority emerges.
The second relates to level crossing protection.
It is conventional in a class of signalling to require a train to obtain an authority to cross a protected level crossing.
Communications base signalling allows a train to communicate its arrival time to the level crossing as part of the process for obtaining that authority. This is another class of time based authority – the train obtains authority to cross at a specified time.
Once communicated, the train is able to regulate its progress safely to ensure it does not arrive prior to the specified time. The crossing is able to ensure that the standard warning is provided prior to the authorised arrival time.
The paper explores the characteristics of, and requirements for time based authorities.
|2016 - April - Naweed and Aitken - Lookout!|
Anjum Naweed BSc (Hons), MSc, PhD, CPE
Central Queensland University
Jeanette Aitken BE (Hons), MEngSc, Dip VET, MIEEE, AMIRSE
Trains are the fastest and heaviest of land vehicles and the intent of railway systems design is to transport them safely and efficiently from one location to another. Track workers and maintainers are the unsung heroes of rail safety but are often placed in dynamic and hazardous situations, rendering them vulnerable to the very things they work to protect. The dramatic irony inherent in their work is addressed by the “Lookout working’ concept of safeworking where a range of technologies are used to assist in the provision of acceptable margins of personal safety from approaching trains.
This technical paper aims to conceptualise the degrees of control and types of technologies used to protect the safety of track workers and maintain the security of their work sites. Presented from a human factors perspective using a systems thinking approach, the paper articulates key lessons that can be drawn from previous accidents and “near-misses” associated with failures in track worker protection, which have been investigated in the context of railways in the UK and Australasia. The objective of the paper is to evaluate the viability of utilising smarter technologies to achieve improvements in maintenance track worker safety within the Australian railway environment.
|2016 - April - McPeake - Axle Counters in Single Line Sections - A Smart Solution to an Old Problem?|
Thomas McPeake MIET AMIRSE
Axle counter technology is a proven, reliable method of track vacancy detection suited for a variety of installations. But despite the many advantages this technology can offer it has not rivalled conventional track circuits as a form of track vacancy detection within single line sections in Australia. This perhaps can be attributed to a number of inherent issues that impeded the effectiveness of axle counters system when configured to transmit data over long distances. However, in recent years there have been a number of advancements in both axle counter and telecommunications technology which have overcome some of these inherent issues. This paper investigates whether axle counter technology is now a smarter solution for single line sections, or if conventional track circuits still provide the best solution.
|2016 - April - Lambla - Driver Advisory System Integration Steps|
Product Manager, TTG Transportation Technology, Australia
In a second stage, we focus on steps for integration of DAS with other railway signalling systems. Integration is inevitable and will add value and capability to the DAS offer. Dynamic optimisation of standalone DAS can deliver energy savings of around 5 to 18% to train operating companies. Integration with traffic management systems (Connected DAS) will allow DAS to dynamically take into account other trains’ trajectory. This will allow to optimise the network capacity.
DAS remains a SIL 0 (SIL 1 in the case of C-DAS) system but can operate with Safety Systems such as ETCS. Integration with ETCS will require ETCS display to be modified so that the DAS graphical interface can be represented on the ETCS screen. This integration to a single visual display will ensure the driver can’t get any conflicting advice between DAS and ETCS. The conflicts will be managed through ETCS accepting or ignoring advice coming from DAS.
|2016 - April - Gray and Alexander - V2X: Vehicle to Everything (Including Rail)|
Paul Gray B.Eng., M.Eng., Ph.D. Cohda Wireless
|2016 - April - Burns - Movement Authorities - A Systems Framework|
Peter Burns MBA, BAppSci (Elect), MIRSE, CPEng, MIEAust
Movement Authorities are shown to be found in all safeworking systems and having characteristics which are common to all of them. The process for issuing a Movement Authority may be characterised as the formation of a contract between the train and the interlocking.
Looking at fixed signal systems, the signal is found to fill three distinct functions, one of which is the communicating of movement authorities.
Turning to ERTMS and CBTC systems, it is shown that their central functionality is of a nature that does not require treatment as a movement authority. Benefits can be obtained by recognising the different natures of the three distinct
|2016 - April - Atchison and Bruce - Implementation of ETCS on Adelaide Metro Network|
Brenton Atchison PhD, BSc, RENG
|2016 - April - Aitken - What they didn't tell you at University - or did they?|
John Aitken BE SMIEEE MIRSE
Aitken & Partners
Simplifying assumptions are a key to understanding many problems and can be very helpful. Thin, inextensible strings and ideal capacitors make for simple analysis but neither is available for purchase, so their practical usefulness is limited.
|2015 - October - Tipper - Signalling the Layout or Signalling the Train?|
Paul Tipper BSc
P.R.Tipper Pty Ltd
The conventional practice of placing signals onto a track layout to meet operational requirements often fails to achieve the aim of the operator. This is because track layouts are developed primarily around geographical constraints and do not consider the dynamics of the operational railway. Equally, signalling which is not shaped by the behaviour it imposes on the train is likely to fail in meeting the operational requirements for the same reasons.
In developing concepts for the Sydney network Sydney Trains has turned the conventional process on its head. The new process started with an analysis of the operational needs to determine the type of train and driver behaviour required to achieve them. This behaviour was then further analysed to determine the likely signalling arrangements which would facilitate that behaviour. Finally, track layouts were devised that were compatible with the signalling arrangements. These layouts were then passed on to the track team to develop into alignments compatible with the geography.