I'll just put that here so i don't have to sign up in github, basically i don't have any models in the tool except Ron's 2ft track pack and Ron's G Scale Track pack, no standard gmod or sprops tracks for that matter...

also i get following lua error when loading a map:

[Track Assembly Tool] lua/includes/extensions/string.lua:87: bad argument #1 to 'string_len' (string expected, got nil)
1. string_len - [builtin:len]:0
2. Explode - lua/includes/extensions/string.lua:87
3. TimerSetup - lua/trackassembly/trackasmlib.lua:1948
4. unknown - lua/trackassembly/trackasmlib.lua:2293
5. unknown - lua/autorun/trackassembly_init.lua:897

also also my gmod crashes after a peroid of time, giving me the reason for the crash that some random model loaded by lua returns NULL or something, every time its an different addon that uses model loading by lua which causes the crash, unless i unsubscribe this addon it seems fixed...