there are two identical trolleys connected by a steal rope so that there weight equals out and the can easily move up the hill.

This is how they move? Pretty slick.

Still there was only a day difference and the same location so I found it interesting how much has changed in that time

I figured this was what you meant, after writing my first comment.

I was thinking of doing something similar, when it snowed here, a few days back. I wanted to take a daily pic of the same location. I ended up with one picture, of the day i had the idea.