This is what I tried:
$ sudo add-apt-repository ppa:apt-fast/stable
$ sudo apt-get update
..........something something.........
.................................................................
.................................................................
W: Failed to fetch http://ppa.launchpad.net/apt-fast/stable/ubuntu/dists/trusty/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/apt-fast/stable/ubuntu/dists/trusty/main/binary-i386/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
I then tried
$ sudo apt-get install apt-fast
but it says:
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package apt-fast