Goal: Realistic / non-magical way to transfer items throughout the server that doesn't rely on glitches or really broken game mechanisms, and that doesn't encourage huge amounts of extra loaded chunks and lag. And that can be done serverside (i.e. not fixing carts)

Solution: a "pneumatic tubes" plugin system that doesn't actually load chunks or require broken supercarting, but does require resource outlay and engineering and effort still.

Details: 1) You build some moderately expensive factory-mod-esque air compressor stations at item delivery and mailing nodes of the system (in cities) 2) You build an unbroken line of stained glass "tubes" (just blocks that form a continuous line) in a consistent color between two stations. You can use multiple colors touching for compact higher bandwidth. 3) You check at the station to make sure "you're getting air pressure" (line is complete). The mod checks the path to make sure it is valid, and registers it as a tube line. 4) You can now put stuff in, and by firing charcoal, push items across the distance. They arrive instantly (to avoid issues with items stuck in the tubes), but the rate of transfer is time-limited. Such as one stack per minute along a single line, or what have you. 5) The plugin registers to listen to successful block breaking events, and checks to see if they are glass. If so, it then checks to see if it's part of a registered tube line, and if so, the line will un-register and report "no air pressure" until it is fixed. 6) The plugin could possibly allow a UI that specifies the recipient, then adds them as part of the citadel group of the destination chest temporarily while the delivery is in progress, so that you can stop randos from walking in and competing with you to click to get your delivery in the post office area. Or some similar reasonable but not bulletproof security. The UI also specifies which color line you want to send stuff on, etc.

The items do not actually physically move through the line, no chunks have to be loaded in between as long as the plugin knows the line is complete (it is until somebody breaks it, doesn't have to recheck pathing each time either).

Thoughts?