The calculation is exactly like it was before. Total number of stations load divided by 220 lbs. to get an estimate of passengers on board, and the number of wagons will be proportional to that.
The only difference is that now you can have up to 5 cars in the wagon IF it's a pallet/ULD loader, the baggage loader with the conveyor belt is still 3 cars at most. Before the patch, it was maximum 3 for both.