The idea of a time waster is to "force" passage of time to make us wait while some imagined activity is occurring on the layout. The time waster is just a one-minute sand timer*, held in a cup made from a PVC pipe cap.
When a passenger train stops at a station, the timer is turned over to begin a one minute interval to allow time for passengers to detrain and board. The train cannot proceed until the time has elapsed.
The hobo camp time waster is explained by this excerpt from the rule book:
Block 16 Trespasser check: If any portion of a freight train comes to a stop at any point in block 16, crew shall check for trespassers aboard the train before proceeding. This may be done by either walking the train, or a slow rollby. This is due to a known hobo encampment in this area. A one-minute timer shall be used to force passage of time before proceeding.
* available from Amazon