what is't?

what is't about public transport that sets
this poet('s mind or muse or spirit) free?
once i've paid the -cough- nominal fee
and taken my seat, what is't that then wets
my stylus' tongue for the rivulets
of syntax and rhythm  that rollingly
flow until my trip's end and carry me
swift past the shores of my joys and regrets?

could it be the white noise of vibration?
the idle time of travel standing still?
the patterns in the chatter i'm a-midst?
i seek, from the bards, illumination;
i'm hoping that this answer they'll distill:
"of poetry and transport; pray what is't?"