Re: "lost" trains

[Jackson Harding <jaxsonjo@camtech.net.au>]

Bill Bolton wrote:
> 
> "nobody" <dweebken@NOSPAM.yahoo.com> wrote:
> 
> > I'd suggest a little technology be put in place. GPS beacons are used in
> > some locomotives - they could be used to indicate proximity to another
> > train.
> 
> And would that have helped anything in the situation under discussion?
> 
> Commercial GPS is not accurate enough to distinguish track position
> except in generally gross situations, i.e. single track, no side
> tracks anywhere in the vicinity.   Its also often not of much use in
> situations involving cuttings etc.
> 
> Cheers,
> 
> Bill

Not so.  DGPS is now available commercially, and there are beacons in
Australia which pretty well removes errors from selective availability,
diffraction and dilution of precision.  This gets accuracy down to 1m or
less in most situations.  Cuttings and tunnels are still a problem
however as they do block the signal.

Jackson
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