Just got back from a weekend visiting my folks in Cheshire, while there we took the kids to Tatton Park farm to see the animals. It didn't take me long to notice rails inset into the cobbles around the farmyard! It seems as though there was hand-operated tramway for moving animal feed around the yard, though it is no longer in use there was a wagon in one of the sheds. The gauge was about 2 foot or slightly over, and the track plan was basically a "Y" leading from a shed, down a hill and to both sides of the yard. There was also a line accross the "Y" forming a triangle, which came out of another shed and crossed at a wagon turn-table without rails - essentially a metal disc.Now this may not have that much modelling potential as it is, but combine the idea with the Lincolnshire Potato Railways, or some of the estate lines, and you could imagine the farmyard line being part of a larger line serving a large estate or farm. As well as flat or open wagons for animal feed, there could be skips for mucking out, coal wagons for the boilers and traction engines, plus general goods, timber, fertiliser and produce! Motive power would probably be open-cab lightweight petrol or diesels, such as a Lister, O&K, Hudson-hunslet or one of those Fordson tractor conversions. Of course a Ruston or Simplex would do too.
I think this could make an interesting micro-layout - probably in a larger scale to allow for the small locos and wagons, perhaps O-14? The farm buildings could frame the scene, with sheds for the wagons to go into, and the line continuing through the gate-house arch to the "rest of the estate". The trackplan would probably need a loop and a couple of extra sidings to make it interesting!