First I thought I can not place the little stations on the sidewalk, because they need to have a certain distance from each other. But nor sir, strangely the criterion is just one station per side of a road segment.
As long as stations on the sidewalk are on different segments of a road, they can be placed right next to each other.
But if there is a segment as long as this one (this one is 7 to 8 plots long)
It is not possible to build another station on the same side of the road. In this case here a station exists at the right end of the road and it is not possible to build another station to the left end of the road.
Now, it would be possible to to split up the long segment, by creating a junction. But what in case, there are houses built all along the segment? Bulldoze for 100k up to 2mil to place a station on the sidewalk?
The algorithm responsible for roadbuilding in cities, sometimes does split up long segments implicitely when it places smaller roads within a large city block. But maybe it did not yet place roads or it will not at all place a junction at this road, or the final segment is still too long?
IMO segments should not be the criterion for how close or far stations can be placed on a street. Additionally, I guess a lot of casual gamers are completely unaware of the segmentation at all and will wonder why they can’t place stations.
Please patch this.