New version: https://factorioprints.com/view/-NO6Lwu5itas4zt8bnUd
Usage
Place the "ServicePickupV6.X" somewhere in range of your logistic network. After the robots finished filling up the boxes somewhat, you can switch the train to automatic so that it fills up with materials. If you ever want to change the layout of the train, just adjust the constant combinators at the wagon you want to change. The first wagon has a disabled constant combinator with nuclear supplies that you can enable. I have it disabled by default, because I usually build my first few reactors at the starter base and don't want it loaded into the train instead. If you change the layout, don't worry about removing the items from the wagon or anything, the system is specifically designed to handle everything automatically and make these one click changes possible. Never put the same item in two different wagons, that completely screws the exact insertion. Also, it's your responsibility to make sure your layout actually fits into the wagon. If you want more than one train, just copy the one you already have or reapply the blueprint. I usually slowly increase the number of trains throughout the playthrough and end up with somewhere around 4 or 5 at 1k spm.
Next, you can place the "Fuel/Trash/MilitaryPickup" and the "Fuel/Military/TrashTrain". These two are seperate, because the train actually has filtered slots and a somewhat complicated layout. If you play without biters, just delete the buffer/requester boxes of the second wagon, because those carry all the military supplies. This wagon is also responsible for nuclear fuel delivery, but it only starts requesting the fuel when at least 50 are available in the logistic network, so as to not drain your entire supply. If you're lazy like me, you can also wait a bit with building this train, because really who cares about trash and fuel.
Now, when you want the train to deliver resources somewhere, build the "ServiceMe" station. Double check that all the combinators, roboports, filter inserters and passive provider boxes are built (that's the number one cause of error). The station should now call a train and unload robots and materials. Construction and logistic robots are automatically inserted into the roboports and construction should start immediatly. By default, the station doesn't unload any nuclear supplies, because that would get expensive very quickly. There is a constant combinator next to the front roboport (marked green in the factorioprints screenshot) that you can disable to allow the train to unload nuclear materials and nuclear fuel. Next to the nuclear constant combinator, there is another constant combinator with some ironplate, copperplate, etc. signals set at 10k. These block the train from unloading the specified items, so when you ever need to block some other items (like rails and electric furnaces in a purple science production) you can add them as a 10k signal to this constant. It basically tells the station there are 10k of that item already here, no need to unload any more. Last but not least, you can customize which and how many military supplies are unloaded with two constant combinators towards the back of the station (marked blue in the image).