Or, when you want to erase the white line, you can use CTRL + Left Click on the "T" picture on your text layer. This will outline the text, and give you the freedom to then go back to the line layer and freely erase without worrying about brush size. It makes it much easier and quicker. From there if you want to delete all the parts of the line that are blocking the text, then you can use the delete key on your keyboard.