Agree with fleetwood on stone scale etc, but great start! Also, I do love the flowers, but unless this is a line used only once a week not much green vegetation lasts very long due to heat. (Perhaps euro trains are cooler?)
Hannes has that great iron rusty in his material clips if the reddish color on Dune's rail has it's own default shader.
That said, this is your render and your perspective, I like it already as is!