Hoo-roo is completely unknown over here in the Land of Hope and Glory... it might be Antipodean, of course. The late Sir Terry Pratchett wrote the definitive guide to Australian usage. TTFN is, to be charitable, long obsolete. AWOL, meaning Absent Without Official Leave, is commonly used and denotes missing, can’t be found at present or simply, doesn’t work.
POS = lacking manufacturing quality, underspecified, or of poor design or concept.
3RO doesn’t appear to be mentioned? I believe this means 3 Rail O, meaning toy-spec O Gauge 3-Rail?
WTB = Want To Buy, also seems to be missing.
DCC over here, always means Digital Command Control, since none of the proprietary O Gauge electronic systems are in any significant level of use - I just skip past any thread relating to it.
O Gauge is generally denoted as 7mm/ft, or 6mm/ft for US prototypes, following the common practice of building models to a certain overall size (US loading gauges being larger than U.K., with European loading gauges being somewhere between the two). 6mm/ft isn’t mathematically correct for 1:48, but it’s little used and no one minds.
N (upper case) denotes a small scale combination using 9mm gauge track and variable scales between 1/148 and 1/160, 2mm/ft. n, lower case, is used inconsistently to denote narrow gauge combinations - On30 denotes 1:48 (American) O scale, 30” gauge prototype but On16.5 denotes O scale, 16.5mm gauge models. OO9 denotes OO scale, 9mm track gauge. OOn3 denotes OO scale, 12mm gauge, representing 3’ gauge prototypes; 12mm gauge also used for TT which is a scale somewhere between 1/100 and 1/120, sometimes 3mm/ft or sometimes a type of motorcycle racing, according to taste.
