minecraft-java-editionminecraft-redstone
I have placed a powered rail on a slope with a redstone torch underneath it as shown in the following two pictures.
Now as you can see, the powered rail is in fact unpowered, despite the redstone torch underneath it.
However, if I place a redstone torch next to the powered rail it is powered, but when I remove it, it continues to remain powered, as it should have done in the first place.
Is this a glitch? Or some behaviour of redstone/minecart tracks that I am unaware of?
I also decided to do some testing on this subject. I placed a powered rail every third track, and these 3 track sequences repeated 8 times.
The minecart (with me in it) initially looked like it was easily going to make it, but closer to the end, the cart only barely caught the edge of the powered track to boost it. Depending on how hard I pushed the cart at the beginning, the cart would only sometimes make it past the final powered track to the lip on flat land.
From the looks of my testing, you could get by with 2 tracks between powered rails for very short inclines, but for carts with no entities inside them and longer inclines, you'll need to put a powered rail every other track piece.
One interesting property of the new powered rails are that they act as brakes when no power is applied to them. Because of this, you can make extremely simple stations like this one:
▮
▓━─━═━─↔
─ rail ━ booster rail
▮ button ═ detector rail
▓ any block
The minecart rests on the slanted powered rail because it the track acts like a brake. When the button is pressed, the track becomes powered and boosts the cart away.
The sequence of detector, powered, detector track isn't a vital part of the station design, but is instead a 2-way booster. When a cart passes over the detector track, the powered rail becomes powered, making a very compact booster. This booster also helps push the cart up the unpowered slanted rail on arrival, resetting it for its next use.
I've been playing around with ways to make a cart magazine that isn't reliant on the cart boosting glitch. However, it's not as simple as constructing something like this...
...as additional minecarts will fall into the bottom one, melding together, instead of stacking.
YouTube user MinecraftAddict developed a hoizontal-cart-magazine-like concept using powered rails like this.
When the redstone is activated, each powered rail will send the cart to the next spot, while the final one will by launched to wherever you hook it up to. However, simply using a button may power the rails for too long and cause some carts to move two spaces, so you may need to use a monostable circuit.
When the button is not pressed, the redstone torch on the side of the button's block keeps the output torch off. When the button is pressed, the first redstone torch turns off, turning the output torch off. At the same time, the repeaters have a redstone signal propagating through them. When the signal finally reaches the output block, the torch turns off again. By adjusting the delay time of the repeaters, you can adjust how long (short) you want the button press to last.
Best Answer
This is a glitch relating to the updating of blocks.
In short, the issue is that when the powered rail is placed, it does not check to see if the block it is on is already powered, but keeps its state until a nearby block updates, such as might happen when you place a redstone torch that would power it.
When that redstone torch is removed again, the track checks to see if it still powered, and, realizing that it is, stays on. (c.f. the glitch that would give free power to tracks placed on a slope when one was removed from a chain of powered rails).
Anything that causes the track to be updated should make the track powered; such as placing the tracks sequentially from bottom to top, meaning that the initial state of the powered rail will be flat: When the next rail is then placed, pulling the end of the powered track up, it updates and gets power.
Another alternative, as Dan F mentioned, is to simply place the torch after the rail.