How do I get the transformNode under root mesh?

[fateriddle 3]

This is a straight forward question, how do I get the transformNode under root mesh?

The asset has a root mesh with id '__root__', putting it in sandbox, I see a transformNode 'node-0' under it, with 3 subMeshes under that transformNode 'node-0'.

So I want to get that transformNode, how?
 

ImportMesh will return all meshes, and I can get access to the root with 

const obj = newMeshes[0]

How do I find that transformNode then?

[Deltakosh 4315]

newMeshes[0].getChildren()[0] ?