|Category: Technical Papers|
|Technical Papers||Files: 20|
|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.
|2015 - October - Palazzi - Railway Capacity - Signalling amongst other influences|
Bill Palazzi B.Eng (Elec.) MIRSE
The layout and configuration of a signalling is a key factor in defining the capacity of a railway. However, the signalling system is not the only factor influencing capacity, and in fact many of the other issues can compromise the capacity delivered by the signalling system.
Capacity on any given infrastructure is partially about what is designed, but is also about how it is operated and what external influences there are. In this way, a railway is less like a measuring tape which provides a consistent and repeatable outcome, but is more like a tool where the quality of the outcome can be poor, acceptable or outstanding depending on the skill of the craftsperson.
To assist the understanding of railway capacity, this paper has outlined a hierarchy of influences on capacity which progressively constrain what is achievable in operation. The hierarchy incudes four levels of influence, as below:
The four tiers of influence help define how the various elements that make up capacity relate to each other, including the relationship between the signalling design and other influences. The tiers also help to clarify where signalling can help, but also the areas where signalling has little or no influence.
Finally, whilst optimising train throughput might be valuable, it is not the only consideration. Attributes such as safety, availability, reliability and quality of service are also important customer expectations; these are reflected in the need to find the most appropriate capacity balance for each railway operation.
|2015 - October - Moore - Signalling Principles of ARTC|
Trevor Moore BEng, MBA, FIRSE, FIE Aust
Australian Rail Track Corporation
The Australian Rail Track Corporation was established in 1998 to manage the below rail assets from the devolution of Australian National Railways. It subsequently set up leases for the interstate rail network in Victoria and New South Wales. It now covers 5 states in Australia. It manages track and access for trains from Kalgoorlie in Western Australia through Adelaide, South Australia to Melbourne, Victoria and on to Sydney, New South Wales and finishing just outside of Brisbane, Queensland. It is an accredited rail organisation and manages rail operations, signalling, track and civil infrastructure.
The signalling principles are represented in signalling standards and in the network operating rules. The Rules detail how the train drivers and the network controllers/signallers view and operate on the rail network.
The signalling principles of a railway cover design, construction, testing, maintenance and operation. All of the System Life Cycle elements incorporate principles that govern the manner in which the signalling system operates.
ARTC has inherited the rail networks, signalling infrastructure and signalling principles of the long standing railways in South Australia, Victoria and New South Wales. For the past ten years these inherited signalling standards have been reviewed and merged. This is an ongoing task and will continue as the railway adapts and grows and new technology is introduced.
|2015 - October - McGregor and Lemon - ETCS and CBTC Considerations for Sydney|
Peter McGregor BEng (Elect) Grad Dip Sys Eng FIRSE
Lead Engineer Signals and Control Systems Asset Standards Authority, TfNSW
Stephen Lemon MSc,Rail Systems Engineering MIRSE
Signalling & Control Systems Manager Sydney Trains, TfNSW
Which technology solution Communications Based Train Control (CBTC) or European Train Control System (ETCS) would be best for fitting to the current Sydney suburban rail network? The answer depends on a number of important considerations: the current needs, the existing state of current signalling infrastructure, risk profile of the railway, short term and long term operational requirements, long term asset plans and of course the available budgets?
This paper explores some of the key influences and implementation issues for using CBTC or ETCS on the Sydney suburban rail network. Many of the issues are not related to signalling principles or technology but involve a whole new way of running a railway. These technologies are “disruptive” to the current operating railway as the implementation involves nearly every part of the organisation: Operations, planning, drivers, guards, network controllers, rolling stock maintenances, track engineers, signalling and communications engineers and of course the railway customers who use the rail network.
|2015 - October - McDonald - When Axles just dont count|
Wayne McDonald BE (Elec), FIRSE
Siemens Rail Automation
Australian Railway signalling has relied on tried and proven track circuits of all technologies for train vacancy detection. Signal Engineers and maintainers assimilated the resolution of the traps and pitfalls through procedures, the school of hard knocks, and mentoring from the industry die-hards. The corporate experience and knowledge has resulted in continued issues being addressed or accepted to the extent that they are invisible..
Enter axle counters. They are not, as some have suggested, the panacea for all train detection ills. While they are immune to ballast conductance, the vagaries of wheel-rail impedance and while they eliminate bonding restrictions they also introduce a whole new set of problems for the uninitiated (gotchas) that require new understanding, new techniques and the application of investigatory skills to resolve.
This paper broad brushes the issues and utilises two case studies, on two different axle counters, to introduce causes of under and over counts and demonstrate a scientific approach to addressing the problems when axles just don’t count properly.
|2015 - October - Marillet et al - Headway improvement through ETCS Level 2, ATO and track sectioning optimisation|
Scott Lister Pty Ltd.
Scott Lister Pty Ltd.
Luke Lee MRailSig BE AMIRSE MIEAust
Scott Lister Pty Ltd.
The trend across the world is for introduction of in-cab signalling to save on infrastructure costs, increase safety and improve performance of railway systems. This is happening today in all suburban networks within major Australian cities.
This paper discusses the potential performance that an automated (GoA2) in-cab signalling system based on ETCS Level 2 with AoE and optimised track sectioning may achieve in a dense suburban network.
To do so, the paper firstly explains the differences between operational and theoretical headways which have been used throughout the paper, followed by principles of the headway calculations for lineside and in-cab signalling systems and the key concepts of ETCS and ATO having direct impact on the theoretical headway. An optimisation methodology for track sectioning is then introduced along with the result of a case study to test its effectiveness on a typically dense suburban network trying to achieve a theoretical headway of 120s.
The results of the study have demonstrated that a significant improvement in the theoretical headway can be made with a major reduction in the asset quantities that is beyond the limit of the conventional signalling system can achieve.
|2015 - October - Hartwell - A Review of the Thameslink Programme|
Georgina Hartwell MEng (Hons) AMIRSE MIET
Network Rail Consulting
The aim of this paper is to provide a project description and update to Network Rail’s Thameslink Programme in London. It discusses the history behind the programme and key design considerations. The paper then goes on to look at the reasons behind the decision to implement ATO over ETCS Level 2, before explaining some of the supporting projects and work-streams. In order to successfully commission ATO, a migration strategy and comprehensive set of system proving is required; testing activities are discussed in the paper. Finally, examples of best practice and lessons learned are given, before highlighting key considerations to be made by other high capacity infrastructure projects.
|2015 - Oct - Tipper and Staunton - Signalling the Layout or Signalling the Train|