So, I started out making a raised ramp instead of a lowered one. So I had to be a bit creative. But I did two loop cuts as suggested and then lowered the ramp itself instead of raising the railings. And - Voilà! Got it pretty fine, I think.
Had to do a bit of a hands-on work with the railings to make them fit to the opening. Actually learned a bit more how the snapping works, and also had good use of “Dissolve Edge”. 
Here is a screenshot from the editor
