Singaporean English - Up-riding
I'm always interested in Singaporean English neologisms that are used in formal settings, for example the use of "handphone" where others might use "mobile phone" or "cellphone". In this case, "up-riding escalator" means pretty much "this escalator goes up" (i.e. the sign's saying don't be stupid and step on the escalator from this end).
Another example of the use of "up-riding" can be seen in this Google cache of a Today newspaper article ("Although there is an up-riding escalator, users have to descend by the stairs at the SGH end.").
The most interesting part of the English language, in my humble opinion, is the grammar used on posters, user interfaces and the like. GUIs like Windows and Mac OS shy away from active voice – to shift blame from computers themselves, it is said; while posters and other instructionally-orientated texts tend avoid gerunds for infinitives (ie, "do not touch" as opposed to "avoid touching" or "touching is forbidden"). Delightfully, "up-riding" not only breaks this trend, but is also probably more elegant than the next alternative that comes to mind, and is not tautologous, at least, if one ignores the graphic indicating the direction of the escalator.
But I'll have to disagree with you on gerunds - I'm very much in favour of plain English, and I think gerunds sometimes sound too flowery. So I think using the infinitive in an imperative way, such as in "do not touch", is preferable to the lengthier "touching is forbidden". (Oh, and "up-riding" isn't a gerund anyway in this context. I can't decide whether I like how it sounds or not.)
I suppose the part about being flowery is at least somewhat right – my bit about gerunds and infinitives was not quite there, ie "no smoking" is really the most ubiquitous of such signs in Singapore. Perhaps signage is an artform like photography – the simpler the better; "up-riding" seems to be a pretty cute way in that direction.