On Oct 10, 11:18*am, The Gardener wrote:
On Sep 22, 12:41*pm, Roy Badami wrote:
I thought moderntrackcircuits transmit a digital code so as to
completely eliminate the risk of traction systems generating the
appropriate frequency?

* * *-roy

You're thinking of the HVI (High Voltage Impulse) type. These are used
where there is a risk of low wheel-rail adhesion causing the train to
"disappear" from the system. TI types are generally more common.


HVI track circuits are hardly modern though. I suspect he's thinking
of something like the FS3000 track circuit from Invensys:

http://www.invensysrail.com/download...4nZFuk9QJL.pdf