MANILA, Philippines?The Manila concert of the band Chicago, originally set Sept. 14, but postponed when key member Robert Lamm suffered a leg injury, is finally pushing through on Tuesday at the Big Dome.

?Surprisingly, people who bought tickets for the original date did not ask for a refund,? said Rene de Guia, whose Ovation Productions is mounting the show. The old tickets will be honored on Tuesday.

Why does Chicago?long past its prime since peaking in the 1970s?continue to attract an audience here? It may be wrong to label it as an ?oldies? band, having released new records in 2006 (?Chicago XXX?) and 2008 (?Stone of Sisyphus?), but it may not be right, either, to consider the group relevant to young music fans.

One factor for Chicago?s sustained popularity here is that the ?classic rock? audience demographic is expanding. This means the college kids of the ?80s, who absorbed their elder siblings? appreciation of ?70s music, now have steady jobs and can afford to buy concert tickets (and maybe the band?s greatest hits CDs after the gig).

Add to that the band?s main fan base, the baby boomers (born after World War II), and a pretty good scenario emerges?not unlike the ones that turn up every time groups like America, the Beach Boys and their ?batch mates? include Manila in their regular tour stops.

Another probable reason for fans? interest to catch Chicago live is that some of them who watched Peter Cetera, the band?s former lead vocalist/bassist, last year also at the Big Dome seemed a bit disappointed not to hear much of the group?s classic songs.

In any case, the current Chicago band lineup still has the original horn section composed of James Pankow (trombone), Lee Loughnane (trumpet) and Walter Parazaider (woodwinds), as well as Lamm (who sang lead vocals on ?Does Anybody Really Know What Time It Is?,? ?Beginnings,? ?Saturday in the Park?).

Jason Scheff, who took Cetera?s place, does not impress some critics who?ve seen how he sings on YouTube. But we?ll see how he fares this time.