Would you read a story like that?

In itself, it is quite good, but I also have a few suggestions for improvement. The first and most important point is that during the whole prologue I don’t really feel like the surroundings.

First of all, it is only mentioned that the wind is strong. Then I don’t think first of all about the roof of a moving train, but just that all of it plays out. It’ll be mentioned at some point, but I couldn’t really start with it. It even confused me where this window suddenly came into play and what it is for one.
At some point it is mentioned that they are on the roof of a train, but even if I read through everything with this knowledge again, I cannot really imagine much. How exactly is Kathi supposed to run on an open window when she’s on a canopy? Where are Joy and Nathan going? The choice of words is also a bit confusing at this point, as I am thinking of getting into a train from the ground rather than from the roof.
I know you don’t want a long description of the environment in a prologue, but if you don’t have one, it’s bad. Just because the whole action is going to be on the train and being followed by any men just don’t really get over
Another thing that doesn’t get over is the setting. When the train came into play, I first thought of Fantasy, who plays in the present world. Then there was a short break when Reiko attacked the sword, but I remained with this view.
Then suddenly the city of dealers is mentioned, which then more me think of fantasy that plays in the past in another world. Of course, the prologue may also include open questions, for example, who are these men? What’s that bag? What exactly is it with the city of dealers? But a prologue should also tune you into history and therefore it would be good if you were introduced a bit into the setting.
You already do that by writing the powers, etc., and it is also something that you can make quite subtle. How is the train operated? With diesel, steam, electricity something magical? Then try to install it somehow, for example by writing the power lines. What clothes do men and Lian wear and the rest? This can also be introduced relatively quickly and subtlely. Maybe Lian is disturbing that his somewhat too big coach pants are blowing up in the wind and blowing around and envying Kathi around her leggings.
Maybe he begins to freeze, because his simple robe does not protect him from the wind, while Reiko envelops his animal felle there is no problem.

Otherwise there are some other smaller things.
When Nathan Kathi throws the sachet, it might be interesting to know in what direction the wind is blowing and in relation to the direction he throws the sachet. I think you want to suggest something supernatural, but if he throws it in the same direction, in which the wind also blows, then it’s actually perfectly normal that it is not distracted.
However, this is a rather tricky point of criticism, as it is actually! if you know the whole context of the scene!

In one place you have a little double. In one sentence, it is said that Kathi has got to grips with the pack and next that she starts running as soon as she has it in her hands. Of course, it is not exactly the same, since in one sentence it is probably meant to catch on itself and on the other that is safe in the hands of holding, but you can also theoretically leave this half-set away.

Next, the already mentioned description would be that Kathi runs on the window. The formulation to run on a certain point is somewhat unhappy, because it is more used (at least according to my experience) if you can see its goal (the window) and can actually go to that. It might be better to say that it runs to the edge of the canopy (then it would be clear at this point that it is a train.)

I also found it a little strange that the men just let Nathan go. It may be that it makes sense in the context of the whole story, but only in relation to this scene one learns that the men are after this little girl who owns the group that also belongs to Nathan. So Nathan might know where to go with it or have other inside information. Besides, he probably wants to prevent the men from coming to the pack. Therefore, it seems strange that they do not take him or try to turn him off. You’re holding him already and you’d have to throw him off the train quickly. (If there is a reason for this, you don’t have to explain it already in the prologue.)

There is also a little word repetition, as though it was risky, he must risk it.

By the way, numbers up to twelve are written out and this is often done (even with short numbers such as twenty or a hundred, but also with longer) because otherwise it can interfere with the reading flow. With your text, that was actually the case with me, as I first read tenth (10th) instead of ten (10).

The phrase “It seemed as the air […] went through by small, blue flashes” doesn’t make sense in my eyes, because small, blue flashes are already very specific and you would have to see them clearly in order to describe them.

In the sentence “Only one last was left” it is still double.

As already said, the prologue is certainly not bad, I would even say he is quite good for the beginning. However, it still looks a bit fast and unthinkable, which is always the case with a first version. Read the best of all again, then word repetitions etc. may also fall on yourself. Also try to put you in a perspective of a person who does not know the whole story and the background.