I feel really demotivated right now because of the mesh limit. I wish to import the train model created in Blender to Studio, which is around 300k tris:
One option is to decimate and have a slightly lower quality mesh. Another option is to separate the model into groups of 20k tris and upload them separately. I would also recommend (if some train cars are identical) just upload them once then copy them in studio.
The new mesh importer allows you to upload meshes with up to 20k tris. This is not the occasion with default mesh parts. You need to use the importer for the updated limit.