I have a C# script that loads a prefab ("test") with terrain. I want the script to move the terrain, but that bit doesn't seem to do anything:

Terrain t = Instantiate(Resources.Load("test")) as Terrain;
t.gameObject.transform.position = Vector3.right * -50000 + Vector3.forward * -50000;

The terrain stays at 0,0,0 as it is in the prefab. How can I move it?