Pretty self explanatory, with my current modset, no vehicles, including SE Space Trains, can actually use any of the power gen options from Space Exploration (or any of the equipment from it, actually). This ends up meaning they are all limited to solar panels until you unlock Fusion Reactors, despite unlocking the RTG's quite a bit earlier than that. (Fusion Reactors are near end game, and so as it currently is, for the vast majority of the game all vehicles will need to run on solar panels. They have varying effectiveness in different zones, though, meaning in some its basically impossible to even run one engine continuously, during day, in a locomotive. Plus with a space elevator, the grid layout a train would need planetside is different than what they would need when at the orbital. Mainly just that a bunch of the solar panels are wasted up there, if you want it to work on the planet. But hey, that could be considered part of the balancing and one of the problems to solve, I guess. I just felt like unlocking the RTG's would be part of that solution?)
Higher tiers of energy shields aren't really that big a deal to be unable to use, given there's basically no way to provide that much power with the small grids and the lack of power generation options (Tier 6 Energy Shield uses a whopping 60 MW of power... how in the nine hells am I supposed to power that? From batteries, really seems to be the only answer). The Adaptive Armor wouldn't have that issue, but also isn't the most important. Also not sure it makes sense thematically to put adaptive armor in a car or not. Not entirely clear what it is, but they do rather look like shoulder guards and cars usually don't have shoulders... Last I checked, anyways. I hardly use vehicles for combat at this point regardless though, got a nigh infinite supply of nukes and those do the job plenty fine.
I'm also not seeing any option for the Power Armor MK 3 equipment, but that was mainly just thrown in later to see if I could get a different power generation option for the trains to work.
I don't have Krastorio 2, if that might have something to do with it. I know that adds a lot of extra equipment grid options, but I kept stalling out on doing SE+K2 and figured just starting with a normal run of SE first might be wise, before trying to extend the thing even further again.
Actually looking through the list of dependencies, despite SE Space Trains being in there, I notice SE itself actually isn't, so maybe this is just a request for support for SE itself. Possibly for Power Armor MK3's equipment too.