Unseen

From the petroglyphs, I saw you,
a yellow engine, pulling thirty four cars.
For a moment I wondered if you saw me too,
red against basalt.

But you, having passed these walls, one hundred,
one thousand times, see only the expected.
Not for you the fading totem or a woman watching,
red against basalt.

Lee Awmiller's Questions:

This is the second poem I have written in my adult life. 

My questions are  Is the cadence awkward? 

Do you "get it"?  Does it evoke any specific feelings? 

If so, what feelings?  Would it be better without the "But" in the line that starts "But you, having..."? 

Would another color be better than red in "red against basalt"? 

How about indigo?  Would "fading idols" be better than "fading totems"?

Thanks!