Quote:
Originally Posted by Silver Fox Phil
As I commented in the thread re the crash in New York, do our modern locomotives and power units have warning alarms and bells if a train is going faster than that permitted?
Not sure if they have?
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Ooops, I was so busy thinking about TPWS that I forgot to mention good old AWS.
Yes in the case of a reduction in Linespeed - of course you DO get an audible warning. (silly me
)
On the approach to a significantly lower Permanent Speed Restriction (IIRC it's 30% or more) there will be an upside-down triangular warning board with the speed written on it, and an associated permanent AWS magnet. As with all AWS warning magnets, failing to press the drivers' cancelling button within 2.2 seconds will result in an Emergency Brake Application.
And...whereas TPWS grids are not provided at Emergency and Temporary speed restrictions, PERMANENT AWS magnets are.
But there is no system to tell you when you're overspeeding. Drivers don't speed deliberately because NR puts people out on the track with speed guns, and more importantly the OTMR (data recorder) logs everything you do. So any allegations by passengers or people who are lineside will be checked. And managers perform regular unanounced downloads also. So it would be silly for anyone to deliberately speed. AS my old instructor used to say, "There are no medals for getting there early, but you'll get the bullet if you do anything silly".
But the technology does exist for what you suggest.
Since modern trains (eg, Bombardier, Siemens etc) already have GPS receivers built into them and 'know where they are' for the purposes of SDO (Selective Door Opening - which is supposed to decide which doors to open on short platforms), it's a small step to program up a computer with the linespeeds to warn drivers that they are overpseeding.
The problem comes when you're on the Mainline and there are multiple lines all close together and with different speeds. GPS can be out by quite a few metres, and AFAIIA Differential GPS, which is a bolt-on enhancement to standard GPS (and is accurate to less than a metre) isn't available on the railway.
But I guess this is probably irrelevant, as the future of the railway is ERTMS. This is in-cab signalling, and the system will continuously tell you what maximum speed you can do, depending on the distance from the train in front. If you don't do what it tells you, it will stop the train. So that ought to be another improvement in safety.
There, that's a fuller to your question. Hope it makes sense.