No, there isn't at all.
Go into my fotopic, read
through the complete list of bus services serving Tampines, and you
would notice that there are only 2 bus services running between
Tampines and the west.
So there is no direct buses travelling between BNL and TAM,
otherwise it would be painfully long!
And so the only way to get between BNL and TAM is by train.
BTW i think it would be better if you post in a suitable question
thread in this forum.