hey, 

is there a way to create a vehicle with a face, like thomas the tank engine, and conrol it's face as you would do with actors?

It is possible.

One way I would do it is have my car with a blank space for the face, then create a separate character. Create the head and program it to work how you want e.g. expressions etc. Once happy, you can attach your head (face) to the car, and use the link tool to link it to the car.

Now where ever your car goes, the face will follow. 

Conclusion, you are making a car (prop) and you are making a character (face/head) and linking them together. They will always be two separate characters. 

thank you. I understand what you mean but I have no idea how to do it... could you point me to any tutorials, please? newbie remark, i have no idea how to link characters,,,

great, thank you very much!