Training drivers on route knowledge and cab controls using simulators has been a useful tool for many years. First developed for the aviation industry, simulators for rail were first deployed in the mid-1960s when the initial electrification from London to Manchester was nearing completion. In those days, real film was taken of the cab view ahead with signals and other trackside elements being superimposed and capable of being programmed to mimic typical operating circumstances.
The simulator technology of today bears little resemblance to those early days. The cab view is now a digitally created image that can be modified when changes to the rail infrastructure occur. Different weather conditions can be simulated showing the impact of fog, snow, torrential rain and even fallen trees, all displayed with 3D graphics and accompanying sound. The view may not be quite the same as real film footage, but it is much more adaptable for training purposes as it can demonstrate a multitude of operational scenarios.
Many TOCs now possess simulators and they have been used on the East Coast franchise for almost ten years. With the franchise now with Virgin Trains, and with ERTMS (European Rail Traffic Management System, a combination of ETCS European Train Control System and GSM-R radio) pending, a complete update of the simulator equipment has been undertaken, ready for driver training when the new signalling system becomes a reality.
As well as having ETCS capability, more powerful graphics and computer hardware have been implemented, along with improved instructor and control interfaces. The simulator provider is CORYS, a French company and a global player in simulator technology for the rail and power industries. In early October, Rail Engineer was invited by Virgin Trains to the King’s Cross simulator suite to see what has been achieved so far.
Designing the requirements
Part of the Virgin franchise requirement was to review all existing simulators and prepare them for upgrade or renewal. Working with CORYS, the starting point was to decide which sections of the East Coast route would be initially modelled, what types of trains needed to be included and the list of operational conditions that would need to be simulated.
For the present, only the Class 91 electric locomotive desk and HST diesel cabs from the original simulator are in place but it is recognised that, in due course, the HSTs will be phased out and replaced by the new Class 800/801 Intercity Express ‘Azuma’ fleet, meaning that a new cab model for the Virgin Azuma is currently being constructed.
Paul Boyle, the Virgin Trains ERTMS implementation project manager, explained that a training base needed to be achieved throughout the length of the East Coast main line (ECML). Thus simulators are provided at King’s Cross, Leeds, Newcastle and Edinburgh. The sections of line modelled to date are Kings Cross to Peterborough, Newcastle to Alnmouth and Craigentinny Depot.
Whilst the precise form that ETCS will take on the East Coast route is not yet set in stone, the intention is that this will be ETCS Level 2 to Baseline 3 specification with no traditional lineside signals. The line-ahead graphics have been produced on this assumption, with ETCS marker boards and balises shown in the anticipated positions. These can be easily modified as necessary to reflect precisely the eventual signalling plan once this is finalised. One feature on the simulator is the use of kilometres and not miles in ETCS mode, since the system is a European standard and Virgin Trains want to understand the implications during the period of debate on changing from miles to kilometres for the UK railway.
As well as normal running conditions, the simulator must model out-of-course conditions. These will include temporary speed restrictions, single line working and permissive working, as well as many different equipment failure modes, plus the more usual but unexpected transition from fast to slow (and vice versa) and junction diversions.
The simulator in action
The room at King’s Cross has been purposely adapted to have a darkened ambience and houses two locomotive control desks (Class 91 and HST), each with a display screen showing the route ahead. For those readers who are familiar with ERTMS/ ETCS operation, the display follows a normal pattern: the permitted speed within the Movement Authority (MA) is shown as a grey circular band on the outside of the speedometer dial, the driver being required to keep the train speed within this limit.
Should this limit be exceeded, an orange warning will flash up as an overspeed tolerance of 3-4kph is allowed without the system taking intrusive action. If the speed should go beyond this tolerance, the orange warning changes to red and braking action will occur until the speed has dropped to below that permitted.
As a train approaches a speed restriction of any kind, so the permitted speed band reduces around the dial and the driver must apply the brakes so as to keep within the new limit. If the MA is such that the train has to be brought to a stand, then the speed band will gradually reduce to zero.
In circumstances where the stopping point must be precise, when the speed is reduced below a predefined value (which varies according to train type and the distance to conflict points), the ETCS system relaxes supervision to allow the driver to stop the train close to the ETCS block marker or buffer stop.
This is known as the release speed and acknowledges that ETCS must allow for a certain level of error within the system’s train position reporting. Without a release speed, the train may be forced to a stand before reaching its intended stopping point, for example before all of the train is alongside a platform. However, the system will never allow a train to reach a conflict point.
A separate indication (planning area) gives a scrolling linear read out on the distance ahead that the MA permits, changes in permitted speed and electric traction features, i.e. neutral sections and pantograph raising/ lowering zones. This display can be zoomed out to 32km so in theory the MA could be seen to extend to this distance, or beyond. This situation will only be present when traffic is light on very long stretches of line without level crossings (such as between York and Darlington).
The planning area constantly shows the 500-metre point ahead, halfway down the linear scale, regardless of the zoom value. This is so that the scrolling objects (such as End of Authority and target speed) appear at a consistent rate within this distance so helping the driver not to misjudge the approach. If a linear scale were used for the entire display, at low speed with a 32km zoom setting, objects would appear almost stationary.
Within the simulator, the train performance characteristics (acceleration, braking, coasting) can be changed. Characteristics representative of a freight train can be modelled by altering acceleration and braking performance. Furthermore, the ETCS braking curves (the data that determines at what point braking must begin and the amount of braking effort that must be used) can be manipulated. For example, a passenger train will be programmed with steeper curves than a freight train because of the better braking performance and hence, shorter stopping distance.
As these curves can be adjusted in the simulator, it is therefore possible to apply the braking curves of a freight train to the Class 91 or HST, thus creating the ETCS conditions which would be applicable to freight trains. It follows that, by altering the performance characteristics and braking curves within the simulator, it can be used to represent any type of train that is likely to use the route.
Next year, the simulator will be upgraded with the recently standardised ETCS baseline 3 release 2. Within this specification is the option to display the new Time to Indication (TTI) alert which appears 14 seconds before the orange band appears on the speedometer. This feature was proposed by the UK to give a conspicuous indication (audible as well as visual) of the impending need to begin braking. This is especially useful when low rail adhesion conditions exist when it is necessary to begin braking earlier than usual.
The current ETCS specification has an optional ‘slippery rail’ function which can be selected by the driver or triggered on the train automatically, for example if the signaller becomes aware of such conditions. Once triggered, this function ‘flattens’ the brake curves to command the driver to brake earlier and lighter.
However, the fixed value of these curves will, in many circumstances, be insufficient or will be overly restrictive due to the variable nature of low adhesion conditions (severity, locations or weather). The TTI option will provide drivers with an alert so that they can react according to the individual circumstances at the time. When upgraded, the simulator will be able to test the effectiveness of this function.
The stopping pattern of a passenger train is not built into the simulation, and thus drivers will continue to need detailed route knowledge and will be responsible for stopping the train at the timetabled calling points.
The ECML still has numerous level crossings along its route and the operation of these will need to be built into the ETCS design. Because of the high line speed, crossing barriers are currently controlled manually by CCTV monitoring to prove that the barriers are down thus allowing the route to be set by the signalling interlocking. A similar arrangement is needed once ETCS is introduced and thus an MA cannot be given until a level crossing ahead is proved closed to road traffic.
The simulator can reflect typical level crossing behaviour in that the MA will not be given until the train is in relatively close proximity. This will maintain road vehicle passage for as long as possible, but still be within time to avoid the need for the train to slow. It is to be hoped that, in time, many of these crossings will be eliminated or controlled differently.
This could mean the crossing being triggered by an individual train’s actual or potential speed, taking into account its maximum available acceleration. This will not happen until after ETCS has been introduced on the ECML.
The timetable for provision of the East Coast ERTMS project has still to be confirmed, but it will be 2020 before the first stage is implemented. This may be in ‘overlay’ mode, with lineside signals retained, and the simulator has to be capable of modelling all eventualities.
Around 350 drivers and management staff will need to be trained, so it will be a lengthy process and no timetable has yet been set for this to commence. In addition to the actual simulator location, an adjacent room has been equipped with screens and monitoring controls to display what is taking place whilst a driver is undergoing training. Thus, any mistakes or suboptimal practices can be observed by others, which will be part of the learning process. It is anticipated that eight trainees will take part at any one time, together with the instructor, at any of the four sites.
The simulator training can never be regarded as a one-off exercise and ongoing familiarity with the system will be needed. To support this, a replica of the simulator will be available for loading on to iPads or tablets such that ETCS driving conditions can be replicated away from the work place. This method will also be used in the classroom environment so that all trainees can operate a simulated train rather than one driving and the others observing.
The Virgin staff are mindful that the East Coast project is not the first in the UK – the Cambrian Line having been converted in 2010 – and also that many ETCS projects are in operation in other countries. Visits have been made to some of these to see what the real operation looks like and to learn from the training methods deployed.
The future of signalling is beckoning and Virgin Trains is well prepared for it.
Written by Clive Kessell
Thanks to Paul Boyle, Paul Lartey, Vicki Havron, Richard Stanton and Neal Smith for facilitating this fascinating visit.