A good yard will have a multitrack engine shed with crawlspaces under locos, as well as having a multi track outdoor sand/fueling track area.
A load test area is for hooking stationary locos up to a huge resistor substation, so that the engine can be tested in high throttle, in neutral without moving.
A Transfer Table, Wye or Turntable is usually there for turning locos and cars.
A modern yard has several recieving tracks where inbound trains pull in, where road locos cut off from the train, and go for maintenance or addtional duties elsewhere.
An escapement, balloon, run around track allows locos to get out of a port/blind yard.
Switching locos either push cuts of cars, or pull them out of the recieving tracks for sorting, eirther by flat switching "kicking", or towing/shoving them to the hump, where they are gravity sorted in a classification yard bowl.
Once sorted, the drafts of assembled cars are towed/pushed to departure tracks, where car inspectors air them up, and inspect for defects.
When train crews are called they get a loco from somewhere else on the system, or at the engine house ready track.
A carman hooks up a FRED telemetry, or flashing Starr marker ... or caboose's are added onto ready for departure trains.
Once head end locos are coupled, and several draftes of cars are added "doubled", a carman gives an initial air brake test. application/release, and gives the go ahead for a roll by inspection, after the yardmaster OK's the trains departure.
Don't rule out 04/06 yards as idea starters ... I actually prefer building routes and laying tracks using TRS2006 ... and later on importing the completed 06 route into a higher version of Trainz.
