On The Battlevan and Trains
Trains certainly exist in the 13th Age, having been invented by industrious gnomes-- equally as fervent miners as dwarves, but rather more willing to develop new innovations to propel their ore-loaded carts.* Some steam, some clockwork, some magical, trains are unfortunately far less useful as long-distance transport in the Dragon Empire-- the earth cracks under Koru footsteps, rising hellholes, hidden caches of undead soldiers, and the thundering roots of the Wild Woods, meaning any laid tracks are unlkely to rest peacefully for long.
Tran, as you'd expect, knows all about every mechanism, ever, and adapted the heavy-duty train engine accordingly. The Battlevan is technically a train hooked up to a powerful magical engine that both propels it and lays track by conjuring small amounts of pure magic force, an adaption of barrier spells. Previous experiments with creating moving rails to drag the vehicle forward at even greater speed drained far too much fuel too quickly, and so this was instituted as the "turbo" function of the Battlevan. The one downside to this method is that, unlike most wizardly spells, barriers draw the solidity of the earth rather than the splendor of the Overworld, and consequently the Van's rails are not so steady in midair. Like earthbound stone, the vehicle seeks to return to the ground. Yet, if these rails could be bolted to the sky, the Battlevan could easily travel to the moon, the sun, and beyond.
The misleading name comes from Cactus' unshakable insistence that the word "train" not be uttered anywhere near him, due to an unfortunate ride in the dusty badlands southwest of Axis. Cactus insists that "van" is a word for "cyclone" or "force", but is a terrible liar and just about everyone knows that Battlevan is just the first thing he thought of. In recognition for his kindness to, well, everyone, it was agreed to let it slide.
*Dwarves work in stone and gems, and consider metal downright reverential-- every Dwarven weapon is a painstaking work of art. Gnomes see metal and the devices easily wright from it as very handy for doing absolutely anything they want, whenever they want to whoever they want for whatever they want. Odds are good there is at least one ambitious gnome behind Regulus.