They should go for freight hopping cutiemarks. I'm sure that'd be an adventure.
This is really cute. It makes me want to grab a box and sit in the back of the train. I particularly like Sweetie's panic and Opal's fed up expression.

Review—
Prompt relevance: very relevant to prompt
Style: uncolored, shaded well, proportions kinda wonky
Background: no background
Story potential: high
Result: Top tier

I love the story potential from this one, as well as the expressions and personality exuded by each of the CMCs. Scootaloo is just having a ball, Apple Bloom is taking tickets in a... Heisenberg hat... and Sweetie Belle is packing far too much for such a short cardboard box trip.

Fantastic

>>Zaid Val'Roa
Cutie-mark Crusaders Train Hobos!
...
Yay!

The faces is what really sells this one.

(Art) Genre: Andy Price

(Art) Thoughts: This looks borderline professional! Are you sure you didn't just swipe this from Andy Price's sketchbook, Artist? :-p (no seriously, j/k, not trying to sling drama here)

While some color would elevate this all the way to the top, I think this is pretty cute just as-is.

(Art Tier): High

There’s a lot of character and cuteness in these figures. Very well done, Artist. Upper tier.