http://www.wymann.info/ShuntingPuzzles/sw-timesaver.html
is about the best of the simple 'shunting puzzle' designs.....''timesaver''.......devised by a famous american modeller.
'Inglnook sidings'' is another simple design...but I prefer 'timesaver'........
The 'key ' to 'shunting puzzles' isn't so much in the actual design...but in the carefully-calculated lengths of the sidings and any run-round loop.
In timesaver's case, the actual size of the layout is entirely dependant on what size of 'stock'..or wagons, one wishes to use.
Also, bear in mind, US freight stock is longer than UK stock......thus for a UK equivalent, more individual pieces of stock can be used.
The size of the shunting loco also is important, as it dictates lengths of headshunt, etc.
I used to have a fully-scenic, US- prototype(?) timesaver........done properly , which also involves a large amount of 'admin', it provided hours of amusement.
Mind, I also used Athearn switchers (SW7) so slow speed running was perfection....especially when compared to UK prototype small shunters of the time (80's/90's)?
The admin involves, clearly 'labelling' each wagon...I used a small, stick-on coloured dot on the roof...quite unobtrusive...but actual wagon numbers were also used.....a bit of a pain if the car was weathered!
one also needs to 'identify' each siding, or placement location....ie goods shed, cattle dock, warehouse, factory, etc.
On timesaver, each siding [spur] might have more than one 'location' on it..ie two factories, or 'customers'...[let's get our prototype priorities right?]....which might involve the temporary 'removal' of a piece of stock, to get another past it?
space-wise, a UK prototype will need less room than a US one.....but if I remember right, I still used less than 6 foot by 1 foot!
In addition, with the 'timesaver' plan, it is also possible to involve it in a much larger scheme.
For example, consider a simple 'oval' layout?
a 'timesaver' plan can be inserted into the oval, in a huge number of combinations.
All one needed to do was enter and exit the timesaver plan on two ends with a direct through route?
ie, for example, enter/exit either end of the loop?
or 'one end of loop, through to the end of a spur'?
etc.
I noted many uK branchline station plans (in model form) used the timesaver scheme...but lost out because of our fascination with passenger facilities.......a timesaver ought to be a 'goods only' plan...although provision CAN be made for the likes of a 'nuisance value' visit from an autocoach/DMU/ doodlebug, to a halt platform located inconveniently?
sorry, were you only keeping a plank?