From Official Factorio Wiki
As of 0.13, the rail planner can be used to automatically place rails. See the page for more info.
- Rail planner tool simplifies rail building.
- Improved the rail selection logic.
- Halved the mining time of rails.
- Removed the curved rail, rail is the only type now.
- Replaced entity type rail with types straight rail and curved rail
- Increased the stack size of Straight Rails to 100 from 50.
- Rails are now crafted in pairs.
- Nicer rail diagonals/turns on minimap.
- Added remnants for destroyed rails.
- Rails are not minable when a train is on them.
- Rails recipe changed, now needs steel and stone
- Rails made more expensive
- Correction of bounding boxes of some built curved rails.
- Rail building and selection boxes