Train (2020)

Set in Nagoya Station, it depicts the encounters of young people who work late at night and what happens after that.

Though it is a parallel world genre, it is similar in:
-the ML doesnt admit he loves FL but everyone knows he loves her very deeply
-serial killer on the loose
-wrong convict
IT IS EDGE GRIPPING, BREATHING TAKING AND HAVING THE SAME SUSPENSE!

In both the protagonist works as police officer and suffers from discrimination, because his father is convicted for murder.

This is a love story in the guise of a serial killer K-drama. The show is about Seo Do-Won’s (Yoon) who loses the love of his life to an act of crime by a serial killer. He gets a chance to travel in a parallel universe where his girl is, in fact, alive. He tries to catch the killer in the parallel universe.

Is not a japanese drama but I think you could like it sinse it has all this mystery around and things you should find, so is fun (at least for me) if you like this kind of dramas where you have to solve the mystery.

Set in the world of television broadcasting, Na Mi-rae travels back in time to prevent her 32-year-old self from marrying news anchor Kim Shin, thus sending her past self down a different path and enabling her to pursue the things she really wanted in life

Crown Prince Yi Gak finds that he has been transported from the Chosun Dynasty to modern-day Seoul. He meets Hong Se Na, who bears a striking resemblance to his dead wife, and is determined to solve the 300-year-old mystery of her death. With his own resemblance to the CEO’s grandson at the company where Se Na works, Gak assumes the identity of the young man to stay close to her. Can the Crown Prince navigate a modern corporation to find clues to his own time period?

Both of these dramas go over the loss of loved ones and the determination to meet them once again. Both of these dramas focus on a murder that happened, and both have a fantasy aspect.
Train is about a parallel universe with dopplegangers.
Someday or One day is about time travel and doppelgangers.
Both these dramas are beautifully made and both keep you on the edge with their plot twists while still managing to be huge tearjerkers.

Both of these dramas have two characters who are intricately involved each other through parental ties as well as a mysterious murder case. In both, the leads travel into different dimensions for each other.
In Train, the ML travels into a parallel universe to protect the FL.
In W, the FL travels into the world of comics to save the ML.
Both of these dramas are beautifully shot and while Train does focus more on the murders and W more on romance, they both give extremely similar vibes when it comes from the transition shots from dimension to dimension.

- Multiverse Theory.

- Both male leads are detectives.

- Mystery - crime dramas.

- In both, we find strange deaths.

Both have a very similar feel to them. In train the ml travels to an alternate dimension in order to solve a serial murder case. And in Kairos the ml gets in contact with a woman from the past in order to save his kidnapped daughter. Though the storylines are different, they both use fantastical elements to solve a crime.

Both are fantasy dramas about parallel worlds and characters from one world crossing over into the other. One is much heavier than the other, though.

Both dramas follow a similar concept: In Train we have someone who switches places with himself of another world, while in "Your Honor" a twin switches places. In both dramas there are cases that need to be solved. If you like the concept of the one drama, you will probably enjoy the other..

Both dramas are about parallel worlds in which there are duplicates of the main characters who live different lives.

Though both the dramas have parallel universe sci-fi shit, Train shows more of a thriller showcase than Derailment while the latter shows more romance.
Even the titles are interlinked.
In Derailment, we see the FL trying to find herself but in Train we see ML trying to find a serial killer. Train has a very subtle romance and isnt the main genre.
But both are very captivating.