Do not be tempted to use railway lines, motorway barriers, fences etc. for connection to radio transmitters. This is strictly forbidden, and 

if caught, you could end up in jail plus a huge fine. These structures all make rubbish antennas for VLF, so will never perform well, as 

the losses are extremely high, and so will never radiate a useful VLF signal. Never be tempted use any public 'infrastructure' as an 

antenna -it just does not work, and will be a waste of effort. 

Regards, David Hine