What is the preposition category of "along"?
Solution 1:
I fear your categorization is based on unsound foundations, but let's just look at along:
The signs were on buildings along Main Street.
Passive.
He traveled along roads that were long and painted purple.
Active.
Assuming that I correctly understand how you're categorizing prepositions, then it's a preposition that can be in either state.
Solution 2:
Along is a preposition of place and direction. Active and passive might work for understanding and visualizing the word but not as standard grammar categories for prepositions.