Train was an astounding drama. Every episode is like a literal roller coaster that builds up momentum until the end of each episode, at the end of each ride (episode), you will be wanting more! The acting, the cinematography, engrossing story, amazing soundtracks that added depth to every scenes and the big to tiny pieces of details that are connected and made a lot of sense.

The story is consistent and logical. Every scenes are well connected to each other; to main plot and to what the show is trying to convey. There are no filler episodes; the plot is tightly packed. It may seem the story is focused on serial killer but it's actually not. The show dealt crime and investigation but in its core, it tackles how our life choices affect us and the others around us without even knowing, and how our choices become our fate that mold our life to who and what we are in the present. That one's choice will not only affect you, but also of countless of other people around you. The two worlds perfectly demonstrated this effect. The "what ifs" of World A were perfectly mirrored and manifested to World B. The characters of both worlds are basically the same but were differently molded by life experiences because of one's choice.

The parallel world execution is one of the best I've seen. Switching between worlds are crystal clear and so clean. You can easily distinguish each worlds by their transitions and color tones. The actors also did really well differentiating their characters from both worlds.

One thing that I wish they were able to do was to explore more of supporting characters backstories especially Do Won B. I was fascinated by the character that I keep wanting to see him more. Sadly, this was only a 12 episode drama that is already tight as it could be and there was no room for more backstories that could potentially slow down an already great pace of the drama.

The acting was very commendable. Everyone did excelllent job portraying their parts. I was completely pulled in especially during emotional scenes. I never ever cried in a heavy thriller drama but Yoon Si-Yoon made me teared up numerous times. His emotions will just draw you in. Portraying parallel characters in this drama is extra difficult because the characters are the same but with different life experiences. So the actors need to simultaneously show similarities and differences which they pulled off really well.

The full soundtrack was amazing. The high bass mid tempo sounds, the revealing deep violin sounds that incorporated in suspenseful events, the combinations of different instruments that are exhilarating, the use of actual voice to create haunted whistlings. Also, the songs "With You" for emotional scenes and flashbacks and superhero-themed like "I Will Never" song that was played at the end of each episode are the best! All of these plus the acting, the gripping story, the cinematography have come all together to create a wonderful drama!