I believe it is better to build a new overpass to replace the Casey Overpass.
Forest Hills Station is a huge hub of trains, buses, school buses and lots of cars already. I travel through the area most times I leave my house, and there is great congestion there every weekday.
Adding more car lanes on the surface cannot help our livability nor walk- and bike-ability.
Keep the folks who are traveling beyond up, and keep our neighborhood less congested.