Cool ideas, Valerik. Currently we're leaning towards a Trans-Siberian Railway connection.
See, right there's the problem Dave...
Trans-Siberian Railway was built across the roof of Russia, deliberately avoiding existing communities.
A one track iron conduit from A to B much like a limited access toll highway through the country.

As in
NO connections, other than to itself...
As late as '74 my buddy Karl spent TWO DAYS on a siding as the hospital trains from the East lumbered by headed for hospitals in habitable parts of Russia, spawned by Sino-Soviet 'Border Incidents'... 48 hours sitting still, all the blinds drawn and nobody seated on the mainline side of the cars, armed guards enforcing the proscriptions. That's a LOT of casualties. & proof the entire road
still wasn't double tracked. I'm not sure it is
now, even today.

All of which is a roundabout way of saying the Trans-Siberian is it's own playing field.
& it takes a train to play, armoured or otherwise...
ALL your action must take place along it, little consequential external input or opportunity exists.
In practical terms a Zeppelin, or cargo freighter, have more believable outside intervention potential than The Trans-Siberian Railway, where any viable force
MUST arrive from one end of the tracks, or the other...
Consider instead the Trans-Caspian Railway, much close the the action, interfaces with diverse communities, cultures, and conditions. Poor roads, primitive airfields, ferry boats, gunboats, and
PEOPLE!! A wealth of Pulp Possibility.

The fluidity of Pulp, it's easy accessibility, and satisfying potential are all rooted in the believable, the achievable, the possible. Stifle all that along a thin ribbon of iron laid through the wilderness "
between Nowhere and Not Much Else" at your Peril Sir!!
Valerik
“Life is like riding a bicycle. To keep your balance you must keep moving”
~Albert Einstein