This isn't our land anymore, kiddo.
There was a time in the past your old grampa here would oversee all of those mining operations, from the Red Hills all the way to the Prima City. It was such a sight - all those white, shiny domes, resting on the red blessed lands of Mars. Heh, Red. Red meant money, back then, kid. Nowadays it means just death and a idiotic flag. Nothing more.
Your gramps was all fine and good, riding under the sun on my trusty Palomino-II rover, keeping an eye on those robotic builders while they put down the tracks for the Red Planet Express, to the notes of "I'm working on a Railroad", a nice, old song from my youth. I don't know, it seemed somehow appropriate.
But them, those dammed reddies showed up. We always thought that it would be aliens, or some sort of magic gate that would wipe us out from this planet. But no, it was the reddies. Those reddies, back from earth. They weren't happy with our claim on this rock, oh, they weren't, I'll tell you that, and they went all North Korean on us. Sent some interplanetary missiles, right down on us. They would take some time to hit Prima City, but that didn't meant we could stay, oh no. We had to leave. Weren't going to be nuked by those reds that easily, oh, no.
So we had to pack up and leave. We had to scramble every single bit of tech we had to transform the Red Planet Express into this damn beast she is today. We put her on tracks, but a different type of track. Tank tracks. We buffed up her engine, we gave her a huge array of weaps and drilling tools to make sure she would be able to clear the way. We made her into this dammed beast, oh, yeah, and your grampa was there to make sure she worked just fine. I handled those nukengines as I would handle my wife, with passion and desire for my work. 'Cause, kiddo, if we weren't fast enough, we would be just bones on the red sand by now.
That's how she came to be, and just a little bit of her huge, long history. She's chugging down nukefuel for sixty years now, and it's nowhere near stopping. And you'll be the one that will make sure she keeps that way, to make sure those cogs don't stop spinning and she doesn't stop cruising the red sand.
We can't stop for long. We need to keep moving, to keep watch of the skies above us. 'Cause you never know when another nuke is coming, and you won't want to be sitting down when it arrives.
So now she is yours to drive, kiddo. Make sure to take good care of it.
I know you'll make Grampa proud.
With those words, the Machinist took out his overseer pin from his jumpsuit. He held it on his hand for a moment, looking at it with eyes that almost gave out sadness. For him, it was the end of a life of dedication to the engines that kept his people and his family alive. But he wasn't able to hold back the smile that slowly crept on his lips. Well, yeah, it may be the end of his story as the Overseer for the Red Planet Express, but it wouldn't be the end of her story. She would keep rolling on the red, dusty surface of that wild planet, running away from an invisible threat that may not even exist anymore.
She would rage on, keeping everyone inside her safe. Keeping his story safe. And, more than everything, giving those people inside her a reason to hope for a future when shouldn't be none.
Sorry for the broken english.