Magiclands subway Bogey problem

[jamal17]

Warning: Progressive meshes are no longer supported by CCP. Though these meshes may work in Trainz, it is recommended that you switch to a LOD mesh.

Error: Unable to load mesh file: 'content 28k7efby709\subway_shadow\subway_shadow.pm'
Can someone please break it down to me and tell me what it means in an understandable way?