Size of DGN file

Hello all,

I think I read all of the file size issues.

I have file where is just cant, placed dynamic template along the 13km track, rails.

The file size is 125Mb which looks big to me and it is keep crashing the Computational design.

I tried to downsize the file by making my tunnel length along track just 2km but file size is same.

Any suggestions how can I downside the file so it will comfortably working within the computational design?

Thank you, Lenka