Normally, you have to set the headlight switch to 'bright with aux'. Some trains even allow you to manually flash them. Which train are you looking for in paticular? EDIT: My mistake... missed the title, sorry!
I think the ditch lights turn on when bell or horn is activated but they flash. I know of a mod that turns them on when the headlights are set to bright and they stay steady until horn or bell is on. https://www.trainsimcommunity.com/mods/c3-train-sim-world/c19-patches/i3329-nyt-small-patches
