A soldier wakes up in someone else's body and discovers he's part of an experimental government program to find the bomber of a commuter train. A mission he has only 8 minutes to complete.

[last lines]
Colter Stevens: [to Goodwin] If you're reading this e-mail, then Source Code works even better than you and Dr. Rutledge imagined. You thought you were creating eight minutes of a past event, but you're not. You've created a whole new world. Goodwin, if I'm right, somewhere at the Source Code facility, you have a Captain Colter Stevens waiting to send on a mission. Promise me you'll help him. And when you do, do me a favor. Tell him everything is going to be okay.
Colter Stevens: Christina, what would you do if you knew you had less than one minute to live?
Christina Warren: I'd make those seconds count.
Colter Stevens: I'd kiss you again.
Christina Warren: Again?
[he kisses her]
Christina Warren: Look at me. Everything's going to be okay.
[suddenly the train explodes]
Colter Stevens: It's the same train, but it's different.
Derek Frost: The world is Hell. We have a chance to start over in the rubble. But first, there has to be rubble.
Colter Stevens: Tell me everything gonna be okay.
Christina Warren: Everything's gonna be okay.
[train explodes]
Colter Stevens: It's the new me.
Christina Warren: I like it.
Dr. Rutledge: Source Code is not time travel. Rather, Source Code is time re-assignment. It gives us access to a parallel reality.
Colter Stevens: You seem concerned about the time. What are you late for?
Max Denoff: I'm on my way to an asshole festival. I hear you're headlining.
Colter Stevens: Oh, that's funny. What are you, a comedian?
Christina Warren: Yeah. He is a comedian.
Colter Stevens: Lily awoke in an evening dress and an opera cloak. In her hand were 5 playing cards. At some point today, you're gonna hear about a failed terrorist attack on a commuter train near Chicago. You and I kept that bomb from going off. If you're reading this e-mail, then Source Code works even better than you and Dr. Rutledge imagined. You thought you were creating 8 minutes of a past event, but you're not. You've created a whole new world. Goodwin, if I'm right, somewhere at the Source Code facility, you have a Capt. Colter Stevens waiting to send on a mission. Promise me you'll help him. And when you do, do me a favor: tell him everything is gonna be okay.
Max Denoff: [telling a joke to the train passengers] Woman always mess up my last name. I was with a girl the other night and she kept calling me "Getoff." She was like, "Getoff! Getoff!" I'm like, "No, it's Denoff. Denoff." She says, "No, you're fat and you're heavy. Get off!"
Dr. Rutledge: You cannot alter this reality while inside the source code.
[first lines]
Christina Warren: I took your advice. It was good advice, thank you.
Colter Stevens: I'm asking you to have the decency to let me try.
Dr. Rutledge: You know, many soldiers would find this preferable to death. The opportunity to continue serving their country.
Colter Stevens: Have you... have you spent much time in battle, sir? Huh?
Dr. Rutledge: That's immaterial.
Colter Stevens: Any soldier I've ever served with would say that one death is service enough.
Christina Warren: I think you broke his jaw.
Colter Stevens: It's okay, he's not any more real than you are.
Christina Warren: I'm not real? How about next time you drive to work?
Colter Stevens: It's not gonna be a next time.
Colleen Goodwin: I want you to concentrate on the passengers in your car. Get to know them. Narrow the suspect pool. Look for one who seems quiet or withdrawn. Who seems nervous. As always, you have eight minutes.
Colter Stevens: Eight minutes and then I blow up again?
Colleen Goodwin: Yes. I need you to discipline yourself on this next pass. Perform only the task that we assign you. Everything else is irrelevant.
Colleen Goodwin: [about the Source Code program] The program wasn't designed to alter the past. It was designed to affect the future.
Colleen Goodwin: If you find the bomber, this second attack - the real attack, we think - can be prevented. We have very little time left. Out here, the clocks only move in one direction.
Colter Stevens: The explosion came from behind me.