Telephone wire, power lines, etc. went over the track on extra tall poles. There was an incident here in Arizona a few months ago where a double-stack container snagged a low hanging high tension power line and ripped it out, causing a widespread power outage. I never did see a followup news item on why the power line was so low, but it had been there for many years without incident.
They are raised above the rails, high enough not to interfere with current or likely future use of the railroad. This usually involves permissions, permitting, etc.