I have tried for some month now to do some re skinning. I downloaded "Train mesh viewer" and "Paint Net" and then followed the different "how to do" from Trainz WIKI . I successfully loaded the Loco on the TMV but cannot open any file with the extension "IM". According to the instruction a folder should have open this file and display some TGA files for editing . This did not happened . So checking back I realize that the mesh Viewer was designed for TR 2009 & 2010. Furthermore simplified instructions from Wiki "how to re-skin" clearly explain for TGA files for which are not there in 2012