Factorio Forums

TL;DR

Double railway track

What ?

Allows to build double railway track at same time.

Why ?

Quick railway roads building...

Nope. It is just complexity for complexity. At the time you have blueprints and construction robots you can place blueprint to have them build easily with any extra equipment around. Manually placing double railway would suggest it is intended way of building rails when single railways are quite good when having single train in some isolated cases. Also that approach would not allow placing curved rails so the rail planner would be useless and with no gap in between it would be forcing the right-hand-side signalling which is not forced by any means in vanilla.

I encountered this in the early stages of the game. I had to deliver oil and iron ore at the same time.