“Assuming your processor is 2.5 ghz or higher and your graphics card is a HD Radeon 4850 or higher you should be fine”

No. This is not enough for CIM2. That games requires a bit more to run as intended.

If TrainFever would be similar in demands, which I guess since it relies on dynamic city growth and stuff like that I bet CPU power would be pretty important in addition to trains and buses running all over the place.
An old Core2 Quad or Phenom II X4 at minimum.

Graphics?
Nothing less than AMD 6000-series or GTX 660