Thanks for making such a clever mod.
I had a suggestion based on a few blueprint books I use for things like rail networks. It would be great to have the ability to create a fork from a given stage and develop parallel stages. To illustrate, the most basic example would be a straight rail segment on Stage 1, then on Stage 2a a tee intersection and 3a an overlapping cross intersection. Then on 2b and 3b you could instead have a small unloading station and overlapping large unloading station, with 2c having a loading station. All would fork from the same straight rail segment and be generated in the same Blueprint Book when exported.