Question about the possibility of Powercivil's secondary programming.

Hello everyone,

I'm from a newly formed BIM develop team from a High Speed Railway Lab in China. We are new to BIM, we haven't decide which platform of softwares to use in the future developing journey. So we are currently researching for information that could help us decide. 

We are currently choosing between Bentley Powercivil and Autodesk Revit. And the situation is we find that Revit is not good at rail, road or tunnel design, and Powercivil is doing great in these direction. But the thing is, we are facing a problem, that the key of our future development is that we may have the ability to write add-ons to help accelerate the designing progress, yet it's not so clear to us that whether Powercivil does provide any SDK or open API or not, while Revit seems much more suitable for secondary programming.

Again, we are new to the BIM industry so we don't know much. If there's any problem with my thoughts about these softwares above, please tell me. And if there's any kind of solution for this, please advise me.

( PS: Please forgive me for my poor English. If any of my expression is not clear or wrong, please leave a comment so I can explain. )