[ARC5] And then there were none

[David Stinson]

As a Railway person:

With the new Positive Train Control system taking charge on the 
railroads, if anything happens to GPS, rail traffic vital to communities 
all over the nation will come to a screeching halt. Trains may run at 
restricted speed, but that backs-up the following trains with 
compounding delays until the whole system becomes paralysed.  Knowledge 
of the previous, successful systems, which are being destroyed, is 
aging-out of the work force which maintains train control systems.   It 
will take many days or longer to "remember" that we could successfully 
run trains without GPS-dependent computers and networks.

That's just one system vital to national welfare.   Many digital 
microwave backbones which connect and coordinate across the country will 
go dark without GPS timing at every station.  A lot of the power grid is 
dependant on GPS timing to run their networks.  Once you have extensive 
and wide-spread power outages, you can soon find yourself in a "you 
don't have the tools, to enable the tools needed to use your tools" 
situation.  If I wanted to bring The West to its knees, GPS would be a 
priority target.
Placing so much dependence on the fragile spider-web of GPS
is just the kind of smug, self-congratulating complacence
that eventually gets us bit.

Dave S.