In strict sense "Railu Katta" is a punjabi word, I have no idea what "Railu" means because we don't use it normal language but "Katta" means baby male buffalo.
I always found it strange that we used to use during our childhood in 80s whenever we used to play cricket. Suppose there are 11 players and we used to make two teams, so 5 used to go in team A whereas the other 5 used to go in team B. Then we were left with 1 extra player who wanted to play at every "cost", so we used to ask him to play as "Railu Katta" which meant that he would bat as well as field for both sides, this "Railu Katta" player used to opt for wicket keeping so that he wouldn't have to run too much during fielding and as a result he would be fresh to bat for both sides. It used to funny as many times this Railu Katta player used to get all the blame that he did favor the winning team and lost "catches" behind the wickets intentionally, we used to call it "Rai karna" in punjabi language.
So I really don't get in which sense Imran khan is using this word "Railu Katta" because it doesn't make any sense to me in reference to which he has used this term, but he is mummy daddy lahori who often uses wrong punjabi words for wrong situations. This was always a problem with lahori guys when I was doing my masters studies in Lahore, the lahoris guys often wouldn't pick the exact meaning of our crude punjabi words that we regularly used in our local punjabi conversations in Gujranwala.