Many official Indian distributors upload Korean movies to YouTube. Channels like Goldmines Telefilms or Cinewave have exclusive rights to certain dubs. Search for the movie on YouTube but filter by "Channel" to ensure it is an official partner, not a random upload.
While there is no "new" version of the original film, the version of Train to Busan (2016) remains widely available on major streaming platforms. You can watch the official Hindi trailer on YouTube . Where to Watch in Hindi train to busan hindi dubbed new