D.A.Stephens
Encompass Engineering Solutions Ltd - UK
How Technologies can be used to
provide flexibility in asset monitoring
1
D.A.Stephens
Encompass Engineering Solutions Ltd - UK
1
D.A.Stephens
Encompass Engineering Solutions Ltd - UK
1
D.A.Stephens
Encompass Engineering Solutions Ltd - UK
ABSTRACT
The UK rail industry has undergone major transformations over the past 7 years; none more so than the development of high frequency fault detection systems.These systems allow more advanced data trending, pro-active maintenance regimes and better, stream lined targeting of maintenance activities on the rail network.
Due to the high volumes of data recorded by such systems, technology has had tobe developed and advanced allowing the storage, transmission and processing of the data whilst also ensuring that the data is seamlessly available to end users from recording to analysis
The Remit
To ensure the seamless and reliable delivery of data from 'X' to 'Y', and to provide the industry with condition data at a higher frequency than the current schedule of 2 to 4 weeks - Simple then!
So where’s the challenge in that?
1. Data is recorded by mobile, and fixed, un-attended systems (No human involvement),
therefore meaning the train could be at any position in the country at any point in time.
2. The data must be transmitted to a fixed point which that is centrally located.
3. This centrally located storage depository must have data processing capabilities enabling the data to be translated into a readable format
4. The data must have the ability to be viewed easily by the end user.
5. The storage location must be connected to the outside world where data can be transmitted to from any location, but still be securely connected to the corporate network
6. Due to the ad-hoc nature of the data being recorded, the solution should take into account that this could happen at any time of the day
The Innovation
The solution was based upon a variety of technologies not seen or used within the rail industry outside of the clean, office based environment and which transformed the way in which parts of the industry now operate.
It incorporated a combination of different technologies including:
- Automatic transmission of data using global positioning systems for reference
- Wireless Local Area Network (WLAN) systems,
- High speed broadband links for data transmission
- State of the art blade server technology
These technologies utilised both window and
Unix operating systems, in a set-upwhich was
specially designed and built using multiple levels
of IT security, including holding areas and
automatic processing systems.
The software was then linked into the corporate
IT network. This meant that data flows could be
established allowing the processed data to be
presented to the end users within the company.
The Realisation
With tests undertaken simultaneously on multiple mobile systems for prolonged periods of time. The combination of all the technologies working together with no human interference, and the realisation that large national companies can utilise such advanced technologies in the harsh environment of the railway will provide huge benefits to the industry. This will still allow large IT networks to be kept secure whilst at the same time providing the ability to move large quantities of data from any point within the country back to a central located storage point. By combining IT and rail specific technologies in this way will drive technology towards greater feats. This is a very exciting time for the advancement of rail technologies and the larger companies need this flexibility to incorporate them.
1. INTRODUCTION
Organisations with multiple assets have thechallenge of how to monitor, manage and maintain these assets. The vast nature of the British railway network means that this industry has one of the largest fixed set of assetsthat an organisation must manage.
Due to the expanse of most railways it is becoming increasingly difficult to manage and maintain those assets to the levels required for high speed, frequent operation of trains. As the population continues to rise and train travel continues to gain popularity, un-planned or ad-hoc maintenance regimes are going to reduce reliability and increase delays.
Post the Hatfield rail accident in 2000 increased emphasis was placed on understanding the state of the network; mainly through asset management. This therefore required more frequent recording of the infrastructure. This was crucial, to not only gain asset knowledge but also to keep the inventory on the state of the assets maintained. It was anticipated that this would mean the inventory could be used to make informed decisions, and to predict and in future prevent asset failure.
This paper will concentrate on the UK railway, however the challenge to monitor and predict asset replacement and maintenance is common to all railways the world over. The UK is currently one of the leading rail industries in developing technological advances in end to end solutions for asset condition monitoring, and in some instances is being used as a show case to demonstrate state of the art technology. This paper will focus on how the UK railway has gone about attempting to collect, store and manage data collected from monitoring the condition of assets. It will provide an insight into the technologies used for data collection, the main emphasis being on the recording of track geometry, the methods employed in transmitting the data, as well as it’s storage and interrogation with a brief overview of way side monitoring systems, and what the benefits are perceived to be.
This paper will show how we have been able to integrate through an expanded programme of works all the various asset monitoring systems. Section 3 looks at the track recording systems developed and the technologies used and how they were deployed, with section 4 providing the brief overview of the way side monitoring systems that have been integrated into the IT architecture. Section 5 describes how the IT infrastructure supported this work, including the use of Wi-Fi technology.This paperwill thenconclude by looking at the lessons we learnt, benefits of the uses of this technology and what further progress could be made with emerging technologies and continued industry support.
2. BACKGROUND
The railway has historically utilised different remote condition monitoring systems to check the current state of its various assets. These systems span different areas including track recording, ultrasonic testing, S & C monitoring systems, weather instrumentationand lubricators. The data collected is typically used to provide more limited information back to a central location. Systems such as these are mainly used to provide alarm information, rather than trend predicting.
Dependant on the system, information is transmitted to a central computer, at regular intervals (eg: daily, fortnightly, or even monthly). These variations make it difficult to trace issues occurring on the track back to the possible cause.
By gaining an accurate picture of assets on a frequent basis, it is possible for the industry to plan maintenance and renewal of an asset in advance of it failing or developing a fault. The result of planning and targeting specific areas could reduce maintenance resource issues, and logically a streamlined process could reduce costs.The ability to trend deterioration in track would also positively affect the running railway by improving journey times, reliability and customer satisfaction.
3. UNATTENDED TRACK RECORDING
SYSTEMS
To move away from the costly dedicated recording vehicles of the past, the use of unattended track recording systemson passenger trains will provide frequent recording of the track infrastructure. This has been made possible in the past few years due to the reduction of core component sizes and cost.
The track recording system used in the project this paper is based upon is a combination of the mechanical axle end mounted system and the optical under-frame mounted system.
3.1 Optical Camera/Laser System¹
The optical system uses camera/laser technology and combines this with a single unit inertial box. The optical system uses standard light sectioning techniques, which involves light of class 3b laser intensity targeting the cross section of the rail head with a camera taking photos at a frequency of 60Hz. This provides a calibrated reference to decipher measurements from. The inertial unit containing a roll and yaw gyro with a lateral accelerometer combined with a tachometer attached to one of the axles, provides the signals that could be converted off-train into useful track quality information.
Figure 1 – Simplified diagram of a track measurement system¹
3.2 Mechanical System²
The mechanical system utilises axle end Linear vertical displacement transducers (LVDT’s), which combined with an accelerometer and gyroscope mounted on the centre-line of the transducer provides wheel displacement measurements which are then translated into useful track quality measurements.
The vertical transducers and the optical system provide redundancy for most of the signal outputs, with the gauge measurement being one that the optical system alone can only measure. The signals from both systems are then recorded as binary data to an on-board PC using ROM-DOS operating system and programming software to manage the signals and file system.
Both systems are installed successfully on in-service passenger trains, such as Class 390 Pendelinos, Class 168 Turbostars and the MkIII High Speed Trains. This provides greater network coverage, and by having two vehicles fitted on any one particular route provides a good level of redundancy.
4. WAYSIDE MONITORING SYSTEMS
Other technologies to which the integrated system was designed for include trackside wheel monitoring instruments, systems concerned with environment, and those concerned with various S&C systems. These all existed prior to the move towards a more integrated and flexible approach to asset condition monitoring and are included in the integrated IT architecture.
With regards to the trackside wheel monitoring systems, two systems were employed - impact detection and wheel trending systems.
The first of these measured an impact force, which has levels set as determined by analysis to pick up on mainly wheel flats. The strain gauges attached to the track measure the level of impact on the rail and provide this as a force measure. This system provides data back for data processing using a standard dial up modem.
The second system was a wheel trending system already proven in Europe but not yet in the UK. It uses a proprietary operating system linked into a Linux and Oracle processing database system. This system comprises of accelerometers attached to the neck of the rail which measure the vibration of the rail as the train runs over. It uses the frequency response from the accelerometers to provide wheel trend information and determines the outputs, relating them to useful outputs such as wheel flats, oval wheels and corrugations.
5. IT INFRASTRUCTURE
5.1Data Processing Centre
Whilst much of the technology has been around for a few years, what makes this project innovative and flexible is the complete end to end solution developed to allow all the systems communicate to a central location for processing.
It is easy to buy an off-the-shelf recording system, but to make it compatible with the UK railway is one thing, to incorporate it into an automated, end to end solution takes it to new levels.
The data processing network has a connection to the outside world which consists of a T1 pipe capable of bandwidth up to 100Mb. Currently only 2Mb of this available bandwidth is used for the system, but having the extra capacity available, allows upgrading to higher speeds within tens of minutes rather than days.
The data storage and processing system
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D.A.Stephens
Encompass Engineering Solutions Ltd - UK
Figure 2 – Railway Data Processing architecture²
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D.A.Stephens
Encompass Engineering Solutions Ltd - UK
was split into three distinct areas. The 'De-militarised zone or DMZ’ acted like a data drop off point, this consists of a blade server array which simply holds the data on arrival from the recording systems. It would then check for viruses. The DMZ is linked to the ‘Development LAN’ via redundant firewalls, the servers in the ‘development LAN’ monitor the DMZ for file’s of certain extension types and copies across the one’s it requires for processing.
We also included modems for legacy way side monitoring systems, however where possible everything was brought in via the 2Mb link, as this was more secure and provides greater
throughput of data.
The processing systems utilised quad processing systems, allowing hundreds of Megabytes of data to be processed within seconds rather than hours. From recording to processing, dependant on the journey the downloading train was on, could be from 6 hours (Longest journey being London to Scotland) to a couple of minutes; the last recordings before entering a download station. Whether it be data from mobile recording systems on trains or fixed way-side monitoring devices the processing system is capable of handling all data types, with a storage are network ‘SAN’ capable of holding 2 years worth of data, equivalent to approximately 35 Terabytes of storage space.
By separating the storage system from the processing servers, provided redundancy and scalability not provided before, using the old desktop type data processing. Servers were hot swappable, allowing replacement with a new or upgraded server within a matter of minutes, with no loss of data, and each server was fully redundant, with automatic switch over.
The processing systems also combines a mix of operating systems, be it Linux running red hat for the Oracle databases or standard Windows 95 for the legacy systems or 2000 for the track recording processing software, all are accommodated.
The whole development network is directly connected to the corporate LAN, monitored by a Network Intrusion Device, which monitors and learns the types of data that is transferred and blocks unusual activity. This allows data to be passed to engineers desktops for data interrogation and analysis securely.
The technologies used in the processing centre were cutting edge at the time of build. To such an extent that it took over 6 months to get a useable Linux build for the blade servers to operate reliably. The whole emphasis is on flexibility, this system doesn’t restrain the uses to regulations other than those self imposed. The potential to provide near real time wheel data to train operators is available through the architecture employed and the ability to transfer data from any recording system is easily configurable.
5.2 Wireless Transmission
Prior to the introduction of the unattended measurement systems the dedicated recording vehicles recorded their data onto CD's, which were then posted or physically taken back to a designated data processing centre. This could mean that there was a large delay between the capture and processing of the data, potentially several days or even weeks. The new method of transferring data needed to be less laborious, more frequent and due to the nature of passenger trains, flexible and unattended.
The emerging Wi-Fi systems allows for the transfer of large amounts of data from the unattended track geometry system using the 802.11b technologies to transfer the data over. By using the wireless communications technology it is possible for the system to move data at a higher speed than the conventional GSM or GPRS methods with a higher level of throughput and reliability.
The track recording system uses a Global Positioning System on the train, not only to provide a location reference to the data recorded but to ascertain that it has reached a data download point. A survey has been undertaken to locate all the major train stations by GPS co-ordinates. When the track recording system locates itself within a 600metre tolerance of a designated train station (whose GPS co-ordinates have been coded into the system as it’s data download point), the train locates its download location in preparation for transferring data. This 600metre tolerance compensates for natural GPS drift and station reflections. The drift was more apparent in London's major stations, due to the fact they are undercover and the areas are more densely populated.
The co-ordinates provide the download location to the train. The train system is allocated a fixed IP address and the router is programmed with the ID of the wireless network in the train station. When the train picks up the signal, establishes a connection over a 128bit encrypted wireless link and the router in the station confirms the IP address, a VPN connection is established from the firewall within the station itself. Once the VPN has connected, the on-board recording system attempts to map a drive to one of the servers in the DMZ. Once the drives were mapped the system seamlessly transfers data. This could only occur if the train stopped within its co-ordinate tolerances, successfully connected and recording had stopped. (Stop was defined as no tacho pulse inputs, lasers off (7kph) and the inertial unit shut down (4kph)).