It works like this:

Make a circle with A and B as the center and an appropriate length as the radius (the radius here is more than half of the length of the line segment).

After drawing two circles, do you find that these two circles have two intersections? If there is no intersection, erase the circle, enlarge the radius and redraw it.

Note: the radii of the two circles are the same!

At this time, use a ruler to connect the two intersections. This will intersect with the line segment AB (that is, the expressway). This point is the midpoint of the AB line, and the station is built here. Of course, the distance to Village A and Village B is equal.

As for the reason, of course, it is because this point is the midpoint of the AB line. According to the definition of midpoint, the distance from this point to A and B must be equal.