I run TS2MAC on the following machine:
iMac (27-inch, Late 2013)
Processor: 3.5GHz quad-core Intel Core i7
Memory: 32 GB 1600 MHz DDR3
Storage: Fusion Drive
Graphics: NVIDIA GeForce GTX 780M 4096 MB
If I say, TS2MAC works fine on my machine in fullscreen mode (but it has evil bugs), you must see, it is a high end machine. If you cut down the resolution and run it in a window, it might work with slower hard ware, but since my time with a PC I don't know any train simulator, that was not resource hungry with one exception: Trainz for iPad, but try to drive "in cab" with a little touchscreen, if you know what I mean. For me it means (it's my humble opinion) N3V knows, how to program a simulator, that is not so hungry for resources (the iPad version shows), but they don't do it. I think, for financial reasons they are very short on man power, the crowd funding of TANE makes me thinking so. Some of the so called "high lights" of TANE are even ready in the third party content like as an example the tilting of the rolling stock in curves: it is realized in HP Trains scenery "Marias Pass X", also "Cab Sway - further support for a user-enabled option for the in-cab camera to also move in response to the external motion (i.e. engineer head wobble)". I need a good railroad sim on mac, this is the reason, I support N3V. Momentarily there is no alternative.
More worse and this I name an evil bug: If you use the surveyor in a route to create a new scenery, it may destroy the route (in that scenery). If you use quick drive, some content may be gone like signals in Marias Pass X and that isn't a fault of HP Trains (they do a very good job) but by the faulty work of N3V. I spent more than 200 bucks for this version of Trainz (inclusive the in app pay ware) not to mention my upgrading the hardware, and I get bugs galore. I hope, that TANE for Mac is downward compatible with TS10 and TS12 pay ware content.
There is many work to finish!!!