Question

how can i make the efx always on, because the game doesn't have much reverb on some routes and i wonder if i could make the efx always on

 

Normally ticking the EFX box in the Settings does that.

 

but when i launch a route, the efx doesn't work even when i'm on a station

 

Whether it is on or not, it doesn't always work. Whether it works or not depends on the people who made the routes. On some routes, you get reverb when you go into a tunnel under a bridge or through a gorge with rock faces on either side of you.