Someone said the diecast Farish body was helping the 08 pull the coaches last night so just to show the Farish 08 power without the die cast body I have redone the test.
Initially due to no body weight, the chassis was only on the rear wheels due to the coupling height pulling it down and still pulled 11 coaches.
Then, I fitted magnet couplings allowing the loco chassis to sit on the rail correctly and added 2 more coaches making 13.
At the end on full speed another coach was added making 14 in total, 15 dragged, so 14 it is which is far more than will be required.