"The Logging Frame Add-On loads short logs. These are only found in Amur, that is the phase 4 DLC region.
The Log Carrier attachment is only available for the Caterpillar CAT 745c truck and loads medium logs.
The Log trailer loads medium logs as well.
The Log Carrier Front and Log Carrier rear together carry long logs.
You need the LP-4 log loader crane to load logs manually; that comes in handy when you have lost a load on the way and want to pack it up again, or when you want to load logs manually at the log station."