NR services run on some public holidays (Christmas, Hari Raya,
etc) & not on others (Chinese New Year). It all depends on
SMRT.
NR services are loop services (ie NR6 starts from Marina Centre
Ter, goes around Sengkang, and back to Marina Centre Ter). Only
exceptions are the bendies which are deployed during the festives
seasons. They run only 1 direction to cater for the heavy load,
after which they go off service back to town for a 2nd trip.