Which is more polite?

[Dally]

Which is more polite?
a. Excuse me, I was wondering whether you could direct me to the
station.
b. Excuse me, I wonder whether you could direct me to the station

Thanx in advance

[The Dude]

Neither. In terms of politeness, they are equal. It's only a matter of tense.

Also, both are very polite!

[Bowdil]

I am not a teacher. In example "b", depending on your tone of voice, it could be misconstrued as you are questioning if the listener is capable of directing you to the station. Example "a" would be a better choice.

[The Dude]

"I was wondering whether you could direct me to the station." (But from your confusion I see that you can't.)

Tone can alter anything.