Question

What about electrons allow them to
be some of the fastest traveling sub atomic particle?

Answer 1

I would say that it is primarily the attraction between the negative charge of the electron and the positive charge of the proton in the nucleus that allows it to orbit the proton at a high speed (sometimes close to the speed of light). 

Answer 2

Electrons can be some of the fastest travelling sub atomic particles because of their ability to gain energy. Electrons gain or lose energy in order to move up or down a level while orbiting the nucleus. Energy is usually represented as E=mc2 and can be measured in Joules which is kgm2s-2. This shows that increasing the energy of an atom can increase its speed.