Bhai...i'm not supporting Mumbai rajdhani here! All trains are equal for me. I still do not favour people debating Mumbai Raj with Howrah Raj in blog posts. But comparing rajdhani with another rajdhani is interesting upto some extent.. like any other Mail/Exp/SF trains we bound to compare each day.
Gatimaan may become the fastest in terms of achieving top speed, but in avg speed, Mumbai raj will surely top the chart. No doubt.