Can you construct a berm? They can be beautiful, if the landscaping is nice, and the mass helps with noise reduction https://cottagelife.com/design-diy/highway-noise-reduction/

Have you hired a soundproofing consulting firm?

Windows leak sound. Any windows should have insulated glass withe one pane laminated at a minimum. Mass helps: concrete, concrete block, insulated concrete forms.

Masonry walls. Triple glazing.

This is not an amateur task. Just the use of the term soundproofing suggests you need professional assistance.

Place less sound-sensitive rooms facing the tracks. Reduce windows and doors on the rr side. Consider resilient mountings for floor and wall structures.

Over the years, I've noticed that rr lines are not as offputting as one would imagine.

Consider this mansion adjacent to CN's main Toronto bypass - the York Subdivision, one of the five busiest rail lines in the country.