Through the use of minecart cramming, infinite storage is possible. If you build one using the schematic on the right, don't forget to put a rail on top of the lower hopper so you can place as many hopper minecarts as you like on it to expand storage capacity. For the minecarts not to spill, it is important to place blocks to both ends of the rail. Be careful to only put items of a single type in the upper chest, you will only be able to access items flowing out of the minecarts into the lower box. As they only flow one by one, different items will only flow out after all of the "same" items are out.
This system has a basic capacity of 118 stacks plus 27 stacks per chest minecart added, so it is very useful for storing items you have plenty of, like stone, or for mob farms to store drops like bone or mob armor.
Design A is probably the simplest. When the hopper has at least one item, it deactivates the Powered Rail so a storage cart coming from right will be stopped under the hopper. After feeding the cart with all the items in the hopper, the powered rail gets reactivated so the cart starts going right. A possible downside of this design is that the powered rail is always active as long as the hopper is empty so if a cart comes to the empty loader it immediately bounces off to the opposite direction. This might lead to an inefficiency of the system if there is a great distance between the loader and unloader.
Design A' is a variant of design A to make it flat.
Earliest Known Publication: 28 March 2013
Design B is a combination of a hopper and a falling edge detector. It activates the powered rail for 4 redstone ticks only at the moment when the hopper becomes empty, so a cart will stop there until you put some items into the hopper and all of those items are transferred to the cart.
For all the designs shown above, minecart with chest will be stuck at these loaders when the cart has no space to receive items from loaders.
Design C has an advantage that, minecarts with chest will not get stuck as long as they are empty while entering the loader. This design has two operational modes: when the loader doesn't have a cart, a small chest that serves as a "buffer" will accumulate items from the large chest above. And when it has a cart, items in the buffer will be transferred to the cart and nothing more. It has a T Flip-Flop that switches between two modes, connected to a detector rail.
Earliest Known Publication: 5 May 2013
Design D will detect if a Minecart with Chest or Minecart with Hopper is full, before sending it back to where it came from. It will only return a full cart. The minecart is stopped by an unpowered, inclined Powered Rail with a Hopper above. The minecart will rest on both the Powered Rail and a Detector Rail with a Comparator checking if your minecart is full. This design works on the principle that a minecart can pass an activated Piston when going uphill, but cannot pass it going downhill. When the minecart is full, the Comparator is triggered, sending a signal to retract and extend the Piston just long enough to allow the full minecart to pass. Set up your rail so the minecart is not going too fast, or it will overshoot the Detector Rail and not return to your unloader.
To achieve the angled Powered Rail facing into a Solid block, first add a temporary Rail (any rail type will work) on top of the block you want your Powered Rail to angle toward, then break that temporary rail and place a Solid block in it's place.
Design E is "stable" in the sense that the Minecart with Chest will keep running between the golden blocks while loading. The Detector Rail between the golden blocks can detect how full the Minecart with Chest is. Once it's full, the "door of gold" will open. All Powered Rail shown here are powered from the side.
Design F mitigates the situation where there are too many items and the chest and hopper become full.
See Simple Automatic Minecart Loading Station - Overflow Protected
Design A is probably the simplest. As soon as the hopper receives at least one item from a cart arrived above, it deactivates the Powered Rail so the storage cart came from left will be stopped on top of the hopper. After taking all the items in the cart, the powered rail gets reactivated so the cart starts going left. A possible downside of this design is that the powered rail is always active as long as the hopper is empty so if a cart approaches to the unloader too fast, there is a non-negligible chance that the cart bounces off before getting braked by the deactivated powered rail. (This will also happen a lot if you use a second hopper below the one doing the unloading.)
Earliest Known Publication: 28 March 2013
Design A' is a tileable variant of design A.
Design B is a variant of design A: It has a detector rail which temporarily deactivates the powered rail to prevent carts from bouncing off.
Design C is a tileable unloader. Larger than design A, but it can hold minecarts with a closed fence gate to prevent them from bouncing off. This design requires that the minecart enters the unloader fast enough to get up onto the detector rail, otherwise it will get stuck on the unpowered powered rail. A single active powered rail two blocks before the powered rail over the hopper is enough to guarantee correct entry.
For all designs shown above, minecart with chest will be stuck at these unloaders when they have no space to receive items from carts.
- InventorTester (28 March 2013). "Extremley Compact Minecart loader/unloader". Minecraft Forum.
- koan911 (5 May 2013). "Detect when chest-minecart is full and launch it?". Minecraft Forum.