No, you can not use a rail or a station/office from the right side before the left side.
When you perform an action that need one of those, you always have to pick up from the most left of your board, this is mentioned in the rules under each action.
You can start use those after the logo when during the 2 last actions you need one and you already reached that level.
You always have to use the leftmost available piece, that's correct.
But you are not compelled to "stop" when you reach the logo.
Let say, for example that you have 3 buildings (2 at the right of the logo and 1 at the left) and 2 rails (both at the right of the logo).
You can use the rails at the right of the logo (they are your leftmost available ones) and that will not trigger the end of the game (because you still have 1 building at the left of the logo).
Hope this helps