Originally Posted by
Chr0m0ly
Is it not possible to adjust the rear cogs distance from the hub?
Uh, No.
"Track hubs have a stepped thread. The main thread that the sprocket screws onto is the same as that of a normal freewheel hub. Outboard of this, is another threaded section of slightly smaller diameter. This thread is a left (reverse) thread, and a special lock ring screws onto it."
-Sheldon Brown
It might be worth reading the article below and then go to look at a set-up FG machine to see how it functions, in particular chain line & tension.
https://www.sheldonbrown.com/fixed-conversion.html
-Bandera