Factorio

So first off I know uploading a blueprint/image is probably needed for full assistance which I can do but not until later. But I am trying to create a blueprint of a city block I created that includes my rails and intersection (2 rails with a fourway at each corner) but I don't seem to understand how to set up the snap to grid because i can't seem to get the rails to line up for the grid. I'm not sure if I am messing up with the dimensions of the grid or with the offsets. Are there any tricks to getting this too work or anything like that?