This fancy elevated rail tunnel represents no Real World structure, it is just pure bling, made simply for the look of it. Each section is the same so they cam be cloned, copied and joined to make it as long as you like. At present there are no corners but there is a ramp that transitions to an underground tunnel.
Riding a Minecart through it can be a bit annoying though because you cannot see the ground outside through the windows from that Minecart. Also, it is possibly a bit dark inside and "nasties" may spawn inside...so that my need addressing.