Cannonball Express 2: Hellbeast of Mars - Cannonball Express: A Sci-Fi Western Book Series, #2

"Wow! It's BUFFY meets FIREFLY on Mars with trains!"Barry J. Hutchison, bestselling author of SPACE TEAM  The job looked like a breeze. Two harmless old ladies seeking rail passage to one of Mars's more distant colonies to visit their dying mother. How could Jess Flint and the big-hearted crew of the Cannonball Express possibly refuse? But those two 'harmless old ladies'? Not what they seem... And when danger diverts the Cannonball onto ancient tracks, unexplored for centuries, the train's treacherous passengers appear determined to show Jess and her friends just how little they all know of the red planet's terrifying past.
Or, indeed, of the Cannonball's peril-packed future. It's a future of blistering action and heart-stopping shocks, as the Cannonball Express finds itself pursued by the circus train from hell, stuck up the solar system's tallest tree, and besieged on every side by colossal Martian snake monsters. A future, in short, that's just about to hit the buffers.