The 24 comments on the article all skip over the fact that there is a sign present in two of the photographs stating that passengers should not pass the sign, and all of the garden is past the sign - so any work on it would be trespassing...
That aside - the piece of the garden at the bottom of the ramp has its outer edge aligned with the platform edge. So, working on it would require either standing on the edge of the built-up sides, or standing on the ballast.
But she's not a passenger, she's a gardener!
Apart from that I agree with your comments.