exporting STL and importing to Meshlab

I have a complex model that seems to have only 2 thinfaces and 1 overhang face, otherwise all other checks are clear in the 3D Print Toolbox. When I export to STL and try to load the mesh in Meshlab, the objects appear for a few seconds, but when the last little bit finishes all objects disappear. I am wanting to use Meshlab as an STL test and cleanup process before I pass it on for 3D printing.

I would be greatful if someone could help me. The model is of the Colorado Street Bridge in Pasadena built in 1913. I currently have the model file running as an interactive display at the Pasadena Museum of History using the Blender app in full screen mode. However, the Museum wants to create a 3D printed model of the bridge for its permanent archives. However, I can’t get the STL file to stabilize. A 3D printing company in Irive is going to print the model (~3’ long) as a donation to the Museum. However, they’re not in the business of trouble shooting files in Blender.

I’ve done a lot of searching on Google and YouTube for a related solution, but nothing’s coming up that’s been able to help. Perhaps someone on this Forum can help. I would readily FTP the file to anyone that’ s willing to look things over and see that you get mentioned on the Museum’s documentation to accompany the model display.