Does the build work locally?

Flagging this with a bit less certainty since I can't see your build logs directly, but this specific error usually isn't a "missing library" problem like it looks — it's the signature of an architecture mismatch between the binary and the host it's running on (e.g. a binary built for linux/amd64 being executed under QEMU emulation on an arm64 builder, or vice versa). The vDSO (virtual dynamic shared object) is architecture-specific kernel-mapped code; when it's asked to dlopen a foreign-arch vDSO, you get exactly this error.

The fact it happens identically on both Nixpacks and Dockerfile builds points away from your Dockerfile/config and toward the build environment itself. Things worth trying:

If you're using docker buildx or an explicit --platform flag anywhere, confirm it matches Railway's actual builder architecture.

Try a completely clean rebuild with no cache (a stale multi-arch layer can cause this even without you specifying a platform).

If you have any custom base image or Dockerfile FROM line pinned to a specific arch variant, check it's not forcing a mismatch.

If none of that applies, this may need Railway to check whether the build got scheduled on a builder host with an architecture mismatch — worth asking them directly for that specific angle.