I'm not entirely sure who Ralph Walker is in the context of the Boston Marathon without further information. But considering the Boston Marathon is a real and highly publicized event, there's a good chance that if there is a story about Ralph Walker related to it, it could be true. There are so many runners, volunteers, and spectators with their own stories. If this Ralph Walker was a runner, perhaps there are official race records or personal accounts from those who knew him during the marathon that could confirm the truth of the story.
Well, without more specific details about Ralph Walker, it's hard to be 100% certain. But generally, there are numerous true stories that come out of the Boston Marathon every year. It's a major event with a rich history, and many participants have their own unique tales. If there are records or eyewitness accounts specifically about Ralph Walker, then it would be more definitive. However, based on the nature of the Boston Marathon being a real event where real people participate, it's likely that his story is true.