Next time, you can post this question on the "question on
MRT/LRT" thread.
As for your question, all MRT tracks in Singapore are electrified
(but not the tracks itself!), just that how they are electrified
depends on the company running the trains.
As for SMRT trains, tracks are electrified by means of a special
rail conducting electricity, known as "third rail". They are seen
as white metals beside the train tracks. And so, SMRT trains are
electrified by the metal contacts attached to the bogie known as
"shoes", which in turn would have some metal floss brushing against
the third rail as the train moves, electrifying the train for
virtually everything from lighting to the train's controls.
And as for SBST trains, if you observe with care you would have
noticed that there are overhead cables on top of the train. And
that as the train runs gradually while you are in the front/back
end of the train looking out to the tracks, you would probably
notice some third rails. As like said, SBST trains would take power
from the pantograph located on the roof of the 2nd/5th coach (if
you are very observant enough), and also from the shoes of the
train's bogies.
