Problem with doing that is the €5 flat starting rate that you have to pay for each file. By having everything in 1 file = 1 start fee = €5, so 4 files = 4 start fees = €20 that is almost a third of the cost of the N gauge Kirow crane.
I decided to put multiple wagons that I had done, in to one file, just to save on this starting cost.
Alistair