Game Object is Instantiating on same position

I am working on a small project . But now I have come across a problem . The problem is the prefab is instantiating on the same position .

I want to instantiate a box end to end . The basic set up is as follows : -

Image 3 -- http://s10.postimg.org/a2cqtappl/image.png

Box game object has a parent empty object (Start_point) , and a child empty object (end point) . Those marks the Start and End of that game object .

The game a empty game object (Tile_Gen) which has a C# script as follows :-

 using UnityEngine;
 using System.Collections;
 
 public class Tile_Gen : MonoBehaviour 
 {
 
    public GameObject G_O_01 ;
 
    public GameObject Current_Tile ;
 
    public Vector3 Start_Position_Of_Path ;
 
 // Use this for initialization
 void Start () 
 {
     Start_Position_Of_Path = Current_Tile.transform.GetChild(0).transform.GetChild(0).position;
     Instantiate(Current_Tile , Start_Position_Of_Path , Quaternion.identity);
 
 }
 
 // Update is called once per frame
 void Update () 
 {
     Path_Generator ();
 }
 
 public void Path_Generator()
 {
     Instantiate(G_O_01 , Start_Position_Of_Path , Quaternion.identity);
 // End of tile position = start tile position
     Start_Position_Of_Path = G_O_01.transform.GetChild(0).transform.GetChild(0).position;   
     print (Start_Position_Of_Path);
 }
 }

Here G_O_01 is Start_point prefab , Current_Tile is Start_point .

But this is not instantiating as I wanted . This instantiates all the object at one place .

But I want something like one behind the another , like this :-

Image 4 -- http://s9.postimg.org/ctwm25m5b/image.png

So Please help me to figure it out .

Regards NB :)