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Originally Posted by RailProject
From what I've read and looked up it seems that most mainline railway lines are powered by 25kV AC 50Hz. Am I correct in this?
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Hmm, I'm not sure I'd say
most. Someone on here may be able to tell you just what proportion of route miles in the country are OHLE/3rd Rail/Not Electrified.
3rd rail 750v DC accounts for nearly all of the South Eastern Region, Southern Region, and South Western region.
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As you pointed out, we would need to know the 'noise' generated by the traction systems/electric motors and also the noise generated by the electrification system.
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Sure, and it's not just noise. You would be looking at some hefty traction currents in the running rails. Several hundred amps per commuter train, considerably more for locos and intercity stock.
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Once these are known we should theoretically be able to filter them out. I've been searching forthis info but I honestly have no idea where to start! There is just so much information around. Any pointers....
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Why not speak to the guys currently doing the job; Network Rail's Signalling & Telecom engineers ?
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I have also been trying to find the characteristics (generally) of a railway line in terms of impedance and admittance (resistance, inductance, conductance and capacitance). With these figures we should be able to work out the 'best' frequency to send down the line.
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I have absolutely no idea what 1 km of steel rail looks like electrically, but from the postings earlier on this thread you can see that the characteristics do change significantly, particularly due to dampness in the ballast.
HTH,
Foggy