My steel mill

[doctorwayne]

And to expand on that a bit: a blast furnace and a rolling mill have several operations separating them, which, in your scene, could occur "elsewhere". Of course, there's also lots of operations preceding the blast furnace and following the rolling mill, also candidates for "elsewhere". The bridge between the two is perfectly plausible. If the track running under the bridge serves only the steel plant buildings, install fencing along both sides of the elevated track. If the lower track serves anything else besides the steel plant, fence-off the steel plant, too.

Wayne