In message , Clive
wrote:
They cope only with difficulty. In DC electrified areas AC track circuits
tend to be used to avoid interference and in AC electrified areas they
tend to use DC track circuits. As you can see there is no third way to use
in dual-electrified areas. I don't know if similar considerations apply to
axle counters.
I understand what you say, but surely there is a frequency that can be
used that isn't a harmonic of either the 25kV or the ripple on the dc?

Yes: it's usual to use 33 1/3, 83 1/3, and 133 1/3 Hz.

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Clive D.W. Feather | Home:
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