Lawrence: Just let me know if you have any questions.
Sheldon: This is a very nice builder's plate. How can you be sure it's not a replica?
Lawrence: Now, that is a great question.
Sheldon: Thank you. I also know the answer. Do you?
Lawrence: Well, there's, uh, rust and soot on the back of it from when it was mounted to the engine's smokebox.
Sheldon: Very good. Ah, the 1947 Santa Fe diesel. I've always loved that paint scheme. I wonder if they had a name for it.
Lawrence: Cat's Whiskers.
Sheldon: Correct.
Lawrence: Ha! Two for two.
Sheldon: Did you know that the word "train" comes from the French verb traîner, which means to draw or drag?
Lawrence: [chuckles] Well, I just learned something.
Sheldon: Well, if you enjoy learning things, then you and I are on the "fast track" to friendship. Speaking of fast tracks, the Japanese bullet train, or Shinkansen...

Sheldon: It's almost opening time. Can I flip the sign?
Lawrence: Have at it.
Sheldon: [pulls out stopwatch] Five, four, three, two, one. [flips sign] We're officially open for business. [Sheldon peeks outside to see nobody waiting for the store] Anticlimactic.

Norman: Excuse me.
Sheldon: Hello. Welcome to the Lone Star Train Museum. I'm Docent Sheldon Cooper. If you have any questions... [taps "Ask Me" badge]
Norman: You know where the bathroom is?
Sheldon: Indeed I do. You'll want to chug along past our authentic Southern Pacific Sunset limited whistle, then keep going past our conductor's uniform, which was worn on the Texas and Pacific Railway. Then you'll come upon...
Norman: Son, I have to take a leak.
Sheldon: It's in the back.
Norman: Thank you.
Sheldon: And our toilets flush, unlike the ones on trains before 1889.

Sheldon: This is a genuine locomotive bell from Texas and New Orleans number 701. Now there's a proper technique to make the purest sound. Most people don't know how to do that. But you're in luck, because I do. [bell ringing]

Lawrence: You want to know more about the Cotton Belt, there's plenty in here.
Sheldon: Although the facts in that brochure are suspect.
Lawrence: [chuckles] Sheldon, I, uh... I wrote this brochure.
Sheldon: While the origins of the Southern Pacific go back to 1848, the company wasn't formally started until 1865.
Sheldon: And before you reprint these, we should talk fonts.

Sheldon: And early trains used the drop chute toilet, also called the hopper toilet, which was really just a hole...

Sheldon: [bell ringing]
Lawrence: Uh... we need to talk.
Sheldon: About this bell? You got it. Did you know different engineers would often...
Lawrence: [stops bell] Son? You're a sweet kid, but... I don't think this is working out.
Sheldon: What? Why? I-I know everything there is to know about trains.
Lawrence: Well, yeah, you see now, that there is the problem. People, when they come here, they want to enjoy it. They don't want to get lectured in the bathroom. And you have been correcting me in front of the visitors all morning long.
Sheldon: Would you prefer I send you a memo of your mistakes at the end of the day?
Lawrence: No.
Sheldon: Because that's what I did for the teachers at my school. I think it brought us all closer.
Lawrence: Sheldon, it's great to have knowledge. But you don't need to show it off all the time.
Sheldon: Oh, I don't mind.
Lawrence: [chuckles] You see, trains are all about balance, right? Now you put too much water into a steam engine, it can't do its job. You let that water run low... Boom, it'll blow up. Now, a good engineer makes sure he uses just the right amount of water. Not too little, not too much. That make sense?
Sheldon: The fireman adjusts the water, not the engineer.
[later, as Meemaw drives Sheldon home:]
Sheldon: And then he took my "ask me" button. He didn't even ask me. He just took it.

Meemaw: Everybody gets fired for something eventually.
Sheldon: For being too good at their job?
Meemaw: Well, Moon Pie, sometimes you just get too excited about sharing the facts in your head.
Sheldon: But learning facts is the ant's pants. Which is the Australian derivation of the bee's knees. See, you just learned something. And wasn't that the cat's pajamas?

Billy Sparks: Hi, Sheldon.
Sheldon: Not now, Billy. I'm in the middle of a math problem.
Billy Sparks: Okay. [chicken clucks]
Sheldon: [checks stop watch] Darn it.

Meemaw: What are you looking for?
Sheldon: Chest hairs. Is there any chance I'll hit puberty in the next few weeks?
Meemaw: Oh, God, I hope not. Why?
Sheldon: The campus is so big, I'll never make it from one class to another without a solid dose of testosterone.
Mary: Maybe they'll let you leave early so you'll have time.
Sheldon: But the end of the class is when I point out the teacher's mistakes. Everybody loves that.
Mary: I'd say run across campus, but I know how you feel about sweating.
Sheldon: It's the urine of the skin.

Mary: Why not ride your bike?
Sheldon: I considered that, but I can't let my colleagues see me with training wheels. They'll think I'm a child.
Meemaw: Can't have that.
Sheldon: Mm-mm. See any fuzz growing?
Meemaw: Let me look. [tickles Sheldon]
Sheldon: Hey. [laughs] No, Meemaw! Bad Meemaw.

Sheldon: Dad, you're a football coach. Do you use human growth hormone to enhance the performance of your players?
George Sr.: We lost our last game sixty-three to nine. What do you think?
Sheldon: I think you should look into human growth hormone. And if you do, send some this kid's way.

Adult Sheldon: With no access to controlled substances, I was left with only one option.
Sheldon: Missy, will you teach me to ride a bike tomorrow?
Missy: Why not Mom?
Sheldon: Working.
Missy: Meemaw?
Sheldon: Old.
Missy: Dad?
Sheldon: Fat.
Missy: Okay. [Sheldon exits] I'm such a good person.

George Sr.: You okay?
Sheldon: My arm really hurts. I want Mom.
George Sr.: You got me. Now, let me take a look.
Sheldon: Don't touch it.
George Sr.: I'm not gonna hurt you.
Sheldon: I'm sorry, but you are too big to be delicate.
Billy Sparks: I'm delicate.

Sheldon: This is bad.
George Sr.: You're gonna be just fine.
Sheldon: This is the arm I write with. This is the arm I eat with. This is the arm I do the Vulcan salute with. Ow.
George Sr.: It's not too swollen. That's a good sign.
Sheldon: You're not a doctor.
George Sr.: But I see this on the football field all the time.
Sheldon: Football players are meant to be hurt. I'm meant to be cherished.

Dr. Patel: Okay. Looks like you fractured your ulna.
Sheldon: Oh, no.
Dr. Patel: Two weeks in a cast, you'll be good as new.
Sheldon: A cast? Don't those get sweaty?
Dr. Patel: Mm-hmm. They can.
Sheldon: And itchy?
Dr. Patel: A little.
Sheldon: Can it get wet?
Dr. Patel: Not supposed to.
Sheldon: Then how am I supposed to take a shower?
Dr. Patel: Well, some people wrap it in a garbage bag.
Sheldon: That's where garbage goes. Did you get a discount doctor because we're poor?

Mary: Don't worry, baby. You're gonna be just fine.
Sheldon: Thanks, Mom.
George Sr.: That's what I been saying the whole time.
Sheldon: But she cherishes me.

Sheldon: Left-handed knocking. Wild. [knocks three times] Georgie?
George Jr.: [o.s.] What? [Sheldon enters Georgie's bed room]
Sheldon: You're left-handed. Now that I've joined your ranks, I was wondering if you could tell me what to expect.
George Jr.: I don't know. To me, it's just normal.
Sheldon: But the vast majority of people are right-handed. There must be some challenges.
George Jr.: It's hard to cut stuff with scissors.
Sheldon: Mom handles most of my cutting needs.
George Jr.: Uh, when you shake hands, it's the wrong hand.
Sheldon: I don't shake hands. It's disgusting.
George Jr.: Oh! When driving, the gear shifter's on the right side.
Sheldon: And I'm not old enough to drive. Being a lefty doesn't seem so bad. I don't know why you complain so much.

Sheldon: Johannes Diderik van der Waals. Nils Gustaf Dalén. Heike Kamerlingh Onnes.
Missy: What are you going?
Sheldon: Listing Nobel Prize winners in physics.
Missy: Why?
Sheldon: To keep me from cracking this cast like a coconut and scratching my skin off.

Sheldon: Well, that's what I heard. And if Hawking doesn't let it stop him, then I can't let this cast stop me.
Missy: Great. Go back to sleep.
Sheldon: I will, and I'll do it all by myself. [sings] Soft kitty, warm kitty
Missy: Oh, my God.
Sheldon: Little ball of fur Happy kitty, sleepy kitty, purr Purr, purr.