While I agree there is a good chance it wouldn't be aloud to leave the siding if it was over the limit, there is no doubt that SCT's PM/MP trains are getting bigger and heavier (a good thing, no arguments here), so how much longer is it until SCT start having to run more trains?
As an interesting side note, I was heading north up the Nexy* early this arvo and noticed a health quantity of SCT Hi-Cube** wagons on the back of an Aurizon
service from Perth, being dropped off in the loop line of the Bolivar Loop (At the North West end of SCT's Penfield depot)
So, SCT are currently putting their "extra" loading on other operators trains as their own appear to be operating at the maxium.
* Nexy = Adelaide's Northern Expressway, crosses the DIRN just north west of SCT's loco and freight depot at Penfield (Good views of the loco depot!)
** Hi-cube is a high roof version of the usual trade mark SCT white vans that they use in Double Stack territory (West of Adelaide & Parkes )