Create a Tack

1) Create a new scene.
2) Take a background image for creating a track.
3) Add a beizer curve.
4) Hide the cube by clicking the eye icon next to the cube in the right side window.
5) Go to edit mode
6) With both the end points selected Select Curve-> Control points-> Set handle type-> Vector
7) Select the first point, grab it and move it to the starting point of the track.
8) Accordingly move and extrude the beizer curve to overlap the background image.
9) To join the ends of the beizer curve, select both the end handle points and press F.
10) Go to object mode, hide the beizer curve and unhide the cube.
11) Change the view to front view and move the cube.
12) Go to the properties window and Select the object properties button.
13) Change the name of the cube to track.
14)  Set the y scale to 8 and z scale to 0.2.
15) To add barrier on the end we need to add a mirror modifier, so go to modifier properties- add a modifier-> mirror.
16) For this track we want to mirror it around y axis so select y and disselect x axis.
17) Go to edit mode, face select mode, select the end faces, press E to extrude, press Y(to extrude in Y direction), press 0.6.
18) Select the top faces, press 'E' to extrude, press 1.6 and enter.
19) Again select the top faces, Press 'S' to Scale ,press 'Y' for Y direction and press '0.8' and enter.
20) Go to object mode and apply modifier.
21) To simplify the geometry we need to delete the faces.
22) For this, Go to edit mode, select the end faces and press 'X' and select faces.
23) Delete all the end faces and duplicate faces like this.
24) In the end to join the bottom faces, select the end edges, Go to Mesh-> Edges-> Bridge Edges Loop.
25) Goto Object mode and unhide the beizer curve.
26) To apply the scaling to the cube, Select Object- Apply- Scale.
27) To have the cube applied to the beizer curve, Go to Modifier properties, Add Array Modifier.
28) Change the fixed count to fit curve and select the beizer curve.
29) To wrap it around the beizer curve add curve modifier  and select beizer curve.
30) Now we have a highe polygon count which will increase the rendering time, to reduce this we have two ways
31) Go to edit mode, Click apply modifier to editing cage in the Array modifer window.
32) Scroll down and in the array modifier section, click Use modifier while in edit mode and click apply modifier to editing cage.
33) Set the x scale to 2
34) Go to array modifier and select fixed count and increase the fixed count.
35) Move the track around the X direction until you reach a straight path
36) To bridge the gap, go to object mode and apply the modifiers.
37) Go to edit mode and change the view to top view
38) Select end faces and bridge the edge loops
39) Object mode and apply scale.
40) Select object-> Snap-> Cursor to center.
41) Select object-> Transform-> object to 3d Cursor.