The God of Nishi-Yuigahama Station by Takeshi Murase

On the first day of spring, a train derails, causing numerous deaths. Two months later, rumors spread of a ghost at Nishiyuigahama Station with the power to send others back in time to the day of terrible accident. The story attracts a woman who lost her fiancé, a man who lost his father, and a boy who lost his unrequited love. A chance to go back, to see those dear to them, seems almost too good to be true. What will they do now that they have it?