mass modelling problem

[ZEICHEN.TRICK]

Hello folks,
I'm new to Revit and I really need to model a concrete sleeper. I've already come relatively far, but now I have to connect surfaces in the upper area of ​​the threshold body and I don't know how to help myself with the Revit tools. How would you continue with my work status?

[barthbradley]

I'm not understanding the question. Is there one?  Are you asking how to cut the Mass to that red profile? Cut the Solid Mass with a Void Mass having that profile.