Here I have some Suggestions:

1. a Train Car and Barge to transport Energy and a Block to unload the Energy
2. a Train Car and Barge to transport Mekanism Chemicals and a block to (un)load the Chemicals
3. a configuration option to adjust the capacity of the Liquid/Energy/Chemical transport Vessels
4. a Locomotive and Tug that uses Liquids as fuel, with Lava as the standard with a configurable Fuelvalue with other liquids addable with a configurable multiplier to the standard Fuelvalue

1. This has been suggested many times but I am really not a fan of that from gameplay perspective. I think it overtrivialises energy storage and transport. Maybe at one point we will do an energetics expansion with hydrogen generation, transport etc. But not a fan of mobile batteries in general. That being said there's nothing stopping someone from making an addon mod with this.
2. This would be nice, but I don't think Little Logistics team (currently myself and @EDToaster) can commit to maintaining another addon/compat mod at this time. It would be cool if another dev took this idea and made an addon. If you think lots of people would be interested in this maybe drop this suggestion in one of the mod idea suggestion channels in minecraft modding discords.
3. Energy tug/charger is already configurable, I may be willing to make fluid storage configurable, but would need a good reason (a specific scenario with listed mods, fluids, and what you are trying to achieve) that shows why the default volume may not be sufficient.
4. Not a fan of the lava approach, seems too trivial/boring imo. A configurable diesel tug/locomotive would make sense but it's not on our roadmap right now. If someone made amazing models for them though I would be more inclined to invest time into it.

Please in the future open a new issue for every suggestion to make it more easily searchable, or even better if you check with us first on discord.

thanks for the feedback, that are just some ideas that popped up in my head while playing around with Little Logistics, Mekanism, Immersive Engineering and Create and yes I could use Create Contraptions, but these make transporting stuff just too easy and they don´t fit the scale of your mod that well and that Railcraft, the best Vanilla scale trainmod ever had configurable Tankcarts, but it got abandoned and sadly never made it beyond 1.12.2, so as it is now to move a lot of liquid I would have to use either one big, ugly create contraption or dozens of your tiny and much better looking Tank Train Cars, I really like the designs of your vessels and that your locomotives are smart enough to find the right way on their own, that makes them so much better to use than Railcrafts
sorry for the wall of text

I kind of wanted to encourage people to use more train cars/barges. My concern is by making them configurable you could get away with just having one train/tug and only a handful barges/cars which is kinda boring compared to long trains imo.

What I meant if you have a picture/description of a specific set up where you are trying to move lots of liquid, and it's way too frustrating to do with 10 buckets per car, I may be convinced to either bump it or make it configureable. But what I wanted to see is long trains with ~10 fluid cars/barges, and maybe multiple trains.