I live in England but have a couple of US outline HO models as I like to run something different occasionally, also the larger number of wheels and weight are useful when running on the garden line as they work the track cleaner train around the circuit. After a season doing so it is time I treated em to some maintenance. It seems that when something is dismantled a screw usually flys off somewhere so I like to have a few spares. Reading online it seems that UNC 2-56 is a common one in use, any suggestions for other sizes that may be useful to have in hand.
G.Harman