Wow you got photos of two s161 buses returning to service
after having their tanks topped... Cool coincidence! 
Yup, but actually they are cameos for today for the two sv 161
buses.. I saw SBS9180E at 1.30pm at Hougang Ctrl (Off Svc route
from HGDEP) then about 2 hrs later spotted SBS894M at Defu Ave 1
(at the junction off Tampines Rd).. both were going to do 161 when
it reached Hougang Ctrl Int and at the same time also spotted
SBS2779A at Defu Ave 1, about to do 107..