Minecarts move slower when using W to accelerate than prior to 1.13

When I played Minecraft in 1.13 or earlier, the minecarts moved at a quicker pace than they do now in 1.14 to 1.15 when I pressed W. Also, they were able to go up hills and on deactivated powered rails when I pressed W. Now, they seem to move at a really sluggish pace, and they can't even go up hills when W is pressed. Is this just a part of the 1.14-1.15 updates, or is this some sort of problem?