a train travels through a tunnel deep within a cave in an underground mine, surrounded by dimly lit rock walls

train tunnel cave underground mine journey travel transportation locomotive tracks dark rocks walls adventure exploration ride subterranean cavern industrial mining passage locomotion vehicle commotion engine railway spelunking excavate subterrene conveyance subterraneous subterranic subterrans subterrel burrow subterrenean shaft galleries subterreneous engineering construction earth subterrenely run commute subway rail