That might be the reason why 9131Y is not in service today,
causing the big mess up of 179... 
Anyway, 3733A of 502 (with destos intact) broke down outside the
old Boon Lay Interchange, along Jurong West St 64, heading towards
Boon Lay Way. The strange thing is, 502 doesn't go there. I passed
the bus around 4.30pm. By 5.30, it was gone though.