Yep, I did a Supply Chain Transformation project as a consultant for GM at Fort Wayne Assembly about 11 years ago.
When they don't have a lot of issues or a lot of cars on hold, staging them in columns like that may delay the column maybe a week at the most but they can normally turn whole staging lots over in three days, 9 cars per carrier one right after the other.
It gets messy when they have a lot of cars with QC issues or can't clear the lot and the line is still rolling. You wind up with completed cars in the middle waiting weeks for problem cars on the ends to clear so the whole column can move. Works well when it works but when it doesn't well.... you know.
Cars that aren't in the staging columns are normally hard MP's. Those are the ones that used to get lost in the system, all it takes is for the car not to be in the assigned space by three or four cars, and then it is seriously lost until they can flag where it actually is, get the part on it, and get it into a staging column. It was a fun gig, they used basically that same system at every plant. MP is NOT where you want to be.
But now since nearly everything they made was technically MP with their massive run-shy policy, I don't have a clue how they're keeping track of what is where and when its supposed to turn out of the staging lots. Plus that process knowledge is over a decade old so....
I'm counting on greed and the pressure to make Q3 numbers as an incentive to get a quicker delivery date, but we are talking about herding goats at this point so, anything is possible.
