THERE ISN'T ONE ANDVERY LIKELY WON'T BE ONE.
There was a training cheat for early versions of FM06, it didnt mess with the code as such, it was a simple bit of fiddeling with numbers in notepad that let you put all the trainin bars to full (and fatigue bar to 0)...you just hadto load and training shcedule and change and numbers in notepad and then load it.
This was quickly fixed, and as it was just an oversight in the earlier game engine and not a 'hack' or any kind it likely wont ever come back.