A simple device like this, that prevents Minecarts from crashing on intersections or junctions if they come in at the same time, can be very useful in more complex Minecart systems that handle more than one Minecart on only one track. I ran into this problem myself while testing out some ideas for intersections in my Minecart system.
In the video I try to explain what actually needs to happen to guarantee a safe crossing of two Minecarts, because it’s not as simple as you would think. You can’t just always slow one cart down to let the other one cross first because what happens is that when the minecart you slow down enters at the right time, right before the second Minecart, there is a good chance they will crash anyways. So what you have to do is make one Minecart dependent on the other one and only slow it down if there really is a second one entering the intersection at the same time.
The redstone to accomplish all that on the other hand is fairly simple, but I had to do a lot of testing to make sure it really works with every timing the carts can have. I build the device so that if only one Minecart comes to the intersection it will never have to slow down no mater which direction it’s coming from. But if two Minecarts come in at around the same time one of them will trigger a detector rail to close the fence gate on the other side just for a short moment so the other Minecart has to wait. But if the second Minecart would have come in slightly before the first one, so it could not have triggered the detector rail in time, its timing would be perfect to cross the intersection without crashing into the other one.
Although this is a fairly simple device it’s still a very useful one and I wouldn’t wanna miss it in my Minecart systems.
World Download: Minecart-Offsetter-1.7.zip