When building Line's it's inavoidable too counter an Un-Removable like an Atenna There multiple ways too avoid thos and some are more efective then others here are a few examples:

Arround

Going arround is a simple an effecient way as long as the line is not too wide and the turns aren't too short. This are best only used in Side Lines

Going under

Going under is just as simple just dig 2 hole's and place the tunnel. of course tunnels can't be signalled so for bussy line's Multiple tunnels for evry track could be required.