You mean the MK2s from that used to be perm on service 52 and 59
transfer to Bedok North in exchange for MK4s ??
(SBS1708L SBS1712Z SBS1717K SBS1720A SBS1721Y SBS1725L SBS1726J
SBS1727G SBS1741P SBS1774U)
Looks like service 52 and 59 will be getting MK4s soon 
