Currently, Railway's private networking is strictly isolated to a single project. If you have services spread across Project A and Project B, they are forced to communicate via the public internet (Public URL).

A very common architectural pattern is having a centralized auth server or a shared database/API in one project (Project A), which serves multiple other independent projects (Project B, C, etc.).

Why the current public-only approach is a pain:

• Need to authenticate the traffic.

• Latency

• Costs

This would be a great change for teams managing microservices or multi-tenant architectures.