Trains can't cover long distances? Surely that's a typo -- trains can cover incredible distances...

And they can change routes within their network. So yes, there's some cost to get train stations and tracks built, but afterwards they can visit anywhere within the network and carry a whole lot more than airships.

Fair point on the oceans thing though.

Trains in tunnels can cross water, and trans-oceanic tunnels are ... within the realm of possibility.

<https://en.wikipedia.org/wiki/Submerged_floating_tunnel>

A fully-automated, cargo-only submerged floating tunnel might be an acceptable pilot / risk model.

<https://news.ycombinator.com/item?id=32967216>

(From a previous airships discussion, as it happens.)