Possible Clues:

• If a cart goes over this rise it may go off
• Raised line of ice
• Narrow hilltop range
• It's clear, say, around the brow of the hill
• Peak journey across German capital
• Top line of roof
• Line where two upward sloping surfaces meet
• Corrugation
• It's good to be carried round the hilltop
• Part of mountain journey across Germany's frontier