International Railway Journal - January 2008 - (Page 31) Main picture: One of BAE Systems’ staff tests a Head Up Display (HUD) on its simulator. Inset left: a mock-up showing what the HUD looks like from the driver’s seat. The green box around the signal head shows the driver where it is. Inset above: ribbon gauges show clear indications of values, as well as their movement up or down. tallest drivers - and everyone in between - can see through it, whilst still being able to operate the vigilance device. While not crucial for this proofof-concept simulator, as the seat height can be raised and the vigilance device turned off, it was something that became apparent from the start and would need to be solved in real-world installations. Experiments were made with a range of methods for displaying information, and different types of information itself. Theoretically, any information available to the driver can be displayed - from signal aspects to schedule information, gradient profiles, and data from the train management system. Initially, speed, brakes and advanced warning system aspect were displayed, but after consultation with drivers, the speed and brake information emerged as a clear favourite. In operation, it is a definite improvement. By displaying the speed and power setting information in the HUD, it is possible to drive the simulator without looking down into the cab. The speed can be displayed as a digital figure, as a vertical speed ribbon (which allows drivers to see incremental changes in speed move up and down a scale) and as conventional analogue-style speedometers. While non-specialists prefer the speed ribbon, the drivers tested preferred the speedometers. The result was a 5-10% cut in driver workload, according to BAE, which has studied this extensively. However, there was no significant change in drivers’ time-keeping, observance of speed limits, and of complying with signals. Despite this, the drivers, all from main line train operators, were overwhelmingly in favour of the HUD. One - and it’s a quote that will be repeated in many places - said: “I’ve been driving for 27 years, and only one hour with a HUD - I missed it when it was gone.” Further development The BAE Systems/RSSB study has shown enough promise for consideration to be given to trials in an operational vehicle, though this has yet to be confirmed, and BAE Systems is positive about the qualities of a HUD compared with translucent LCD screen. Davies says that one of the great advantages of a HUD is its flexibility as it allows anything to be displayed at all, meaning that after an installation, operators could add functionality to it. An example of this is demonstrated on the simulator, where signals are highlighted in a green box in the HUD. At busy junctions where there are many signals, this shows immediately which applies to the train, though by Davies’ own admission, the route knowledge of drivers means this is an option few if any operators would go for. It does demonstrate, however, that extra functions can be added, and BAE expects operators to come up with hitherto unknown applications for the technology. One area where HUDs will prove useful if adopted is in conjunction with ETCS, which displays a massive amount of information on a computer screen - from speed curves, to advance notice of speed limit changes, and more still. At present, it’s unavoidable for a driver to look down at the screen, but used with a HUD - perhaps with selectable display modes on the throttle control - it could be made much easier to use. It is early days, but the BAE Systems/ RSSB study is conclusive - HUDs do improve a driver’s lot. Justifying it commercially for operators in terms of efficiency gains may prove to be another question, but if you ask pilots whether they prefer to fly with a HUD or without, you’ll get a near unanimous vote in favour, and with trains getting more complex, in 20 years time, train drivers may well say the same. IRJ IRJ January 2008 31
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