I carry trains but never ride, with twin paths running side by side. I cross the land yet never roam, what am I that leads them home?

The whole idea is for me to stay low. It’s been said, I’m carried by the wind, only some people will know.

I’ve always been yours. Though you get no credit for creating me, still I’m anything you want me to be. You can’t physically hold me, although everyone is trying to get a grip on me. What am I?

I'm magical with war. I'm twisted with dread. I'm a passage with air. I'm impassible when dead. I'm immovable with a grid. I'm held with head. I'm secure when pad. I'm deadly as a hem. I'm united when wed. I'm alone with love.

I am white, but I am not snow. I am sweet, but I am not candy. I am a powder, but I am not sand. I dissolve in water, but I am not sand. What am I?