I have not played it myself yet, but when I first looked into the game I came across a few gameplay videos on niconico which made it look to me as if it's basically A5 - in terms of gameplay and presentation - with a story aspect bolted on. And since I'm not the biggest fan of A5 as it is, a more linear and scenario-focused version of that game was the last thing I needed. Therefore I didn't look much deeper into it, and I don't think it's available on the PSN store anyway. At least it wasn't back when I bought AIV & A5.
The PS1 version of A5 isn't very attractive to me either, as I much prefer the PC version's customizable GUI and 3D acceleration options. A-Train Z still looks interesting because of the story element, though, and I hope it might be translated decades or so from now. I don't know if director Iizuka worked on it, actually; that would make this a major link between AIV Evo and the current handheld series. A5's PS1 port was handled by a team different from his, so there's some mystery here.
Yes, I absolutely agree. AIV is really one of the rare cases - in terms of city building/transport sim games - where the Playstation version is even superior to the PC version. Games like SimCity 2000, Railroad Tycoon 2 and Transport Tycoon were an absolute nightmare on Sony's console in terms of performance, load times and interface. AIV by comparison has such an elegantly designed interface and runs so smoothly, it's a joy to play.
Do you have a PS1 mouse? Just curious to know if the game handles well even via d-pad (can't remember if analog's supported). The game I'm certain influenced Maxis to include a 3D view in their PS1 version of SimCity 2K, lol. And the Artdink game's 3D view loads surprisingly fast given how early it launched, which helps if you're wanting to immediately luxuriate.
I have to say it's nice and refreshing to see someone with so much appreciation for Artdink. As much as I love mechs in general and Gundam in particular, I sometimes feel it's a shame that this - along with other licensed anime games- is what they are now stuck with. I enjoyed my time with the Gundam Seed Vita game, but they have so many quirky and unique games in their back catalogue that it somewhat feels like wasted potential. One of their franchises I want to give a shot at some point is the Atlas series, but I haven't yet found any helpful online ressources in terms of how to play them.
Studio Artdink seems like a smart business move, necessary for their corpus to survive and keep making the games they had been up to the point of financial exhaustion. Artdink's currently hiring new university graduates for positions at both departments; I think A-Train DS/3DS' success, along with a recent Carnage Heart revival, shows Artdink can still revisit their old IPs somehow. Iizuka can't do both A-Train and Carnage Heart simultaneously, though, and maybe they don't feel as confident about giving new and old employees opportunities like they used to. I don't yet know how to play The Atlas or Neo Atlas either, but translating Artdink's back-catalog is a priority for me and for others (Lunatic Dawn: Passage of the Book is being worked on right now!).
In the meantime I hope A-Train 3D does well enough to give the franchise a further push in the non-japanese parts of the world.
I know this is more of a transportation simulator but eh 
