Minecraft wiki entry for Minecarts, associated text: When minecarts travel upslope without having sufficient stored momentum, a powered rail is needed 1 every 4 blocks to sustain movement all the way to the top of the slope, Alternatively, 2 every 8 blocks are somewhat easier to supply power to (note that this doesn't seem to be working as of patch 1.14.4, and may require additional testing) However, note this is a worst-case scenario where there is no momentum to start with.