In the CM there should be a tab: "Import Content" or something like that, and you point it towards the downloaded unzipped HOG file, or you can copy the contents of that zip file, to another file location, to import those HOG textures.
I have all the textures installed, they don't take up much space on my cheepo integrated graphics Vista laptop :hehe:
It took me 2 weeks to get HOG textures into Trainz in 2007 ... I was a big fat dummie back then ... now I am just big and fat.
I think I drove Slavedriver and others nutz ... as I was an absolute PC Dummie ... now I'm just a Dummy !