Cutting a model according to construction phases

Hi,

I'm generally working with OpenRail Designer but this is not a rail specific problem.

The problem is as follows: We have made a 3D model of a train station with the help of several other planners. Our model includes rails, sleepers, etc. but also platforms and other objects. This is to say we have a mixture of meshes and volumes in our model. Now our goal is to visualise the construction process. When which turnout is deconstructed when it is rebuilt and so on for every element in the model. This is intended to be done with OpenBuilding Designer and attributes. The difficulty now is to get from the big model to the cut up (according to construction phases) model. These individual parts should retain their respective volume information so that later one can read out the information of materials per construction phase. 

We have tried it by making a named boundary around a test part and doing a quantities report by named boundary while displaying that named boundary only, then we've made a saved view, which we then attached to a new empty file and finally merged that saved view into master. This seemed to mostly work until we merged the saved view into master. The mesh of our ballast had created new lines and connections with itself and also lines that went into nothing. It slightly resembeld the chaotic paintings I would make whith paint when I was bored when I was younger. The volume information also seemed to be lost. 

I've attached a result of the excercise for those interested.

I'm hopeful some of you might help weed out the problems in our approach or maybe even provide a different approach, as long as it works.

 proj_2025_200_a_615.dgn