Bagagetrains running into eachother only happens when your using multiple trains. If you just use the same 2 trains everytime, than there's no conflict in collisions.
No, first because we are not using the "same" trains, but also because starting times are randomized so a vehicle departing from its starting point might conflict with one arriving from the airplane.
For example: the 2 bagagetrains drive from the terminal to the airplane, unload everything and drive back to the terminal. Than the animation starts all over again with the same 2 trains coming from the terminal to the airplane until the preset time has expired. That avoids collisions between vehicles.
No, this won't solve anything. You must understand that, it's not an "animation". Once vehicles detach from the airplane, they are not animations anymore, but full-blown ground vehicles that will have to follow unpredictable paths of not foreseeable lenghts with randomized timings either in order not to look too predictable. So, please, when I've say it's not SO easy, please accept it.
Which doesn't obviously mean it's not doable, but it's not as simple as it seems.