Wait till you see the crowded NB platform at Yishun everytime a
fully loaded JE-bound train pulls into the station...
Yew Tee (Southbound) also I think, almost
the same crowdness as Yishun. As the shuttle train has to
terminate at Yew Tee, passengers who continue journey to Kranji and
so on... have to wait for another train.
Yes, the crowded NB platform at Yishun are supposed to wait for
the next train since shuttle train terminates at Yishun.
To conclude, most of passengers who take the shuttle train
earlier on are managed to squeeze in the next train since some of
commuters are also alighted at Yew Tee or Yishun.