往前 means "to move forward" and 走 means "to walk", "to go". Also, the former and latter characters have their own meanings related to a movement of "go".
There isn't a repetitive meaning in 往前走.
往: towards; in the direction of;
前: forward; ahead;
走: go; walk;
往前走: walk in the direction of 'ahead'
It might not be grammatical English, just to explain Chinese.
往 can be a preposition to mean towards and, as a verb, to go. In 往前走, it's used as a preposition.
This example should warn us not to convert / translate too directly when dealing with languages.
As explained by other contributors, 走 in this phrase is not a repetition; it appears so only when a direct conversion is made into English.
往前 is used when merely indicating or moving or wishing to move towards a certain direction.
往前走 is used when physically walking or driving towards that direction.
Btw, there is also 前往 which is more for a planned journey to be taken shortly.