WARNING: Spoilers from recent chapters. Hat-lady Poll

[irishock]

The way the lady dresses and walks has to be Fusae in my opinion. She doesn't look mid 30's, but rather in the 40's. Yukiko dresses like she's 20, no?

[Kor]

As this is opinion after all

Hat lady = Okiya's Friend, Okiya = Okiya, Scar Akai = Akai, Amuro = Amuro

Aha, and Bourbon?

= the drink that Okiya might drink, and if I remember Jodie and James Black bought.

A word to play on Gosho's fourth wall, like a cliffhanger. Something that is used but will never be resolved to keep them coming back for more.

So you still didn't let go of that...

[doublemoonlight]

As this is opinion after all

Hat lady = Okiya's Friend, Okiya = Okiya, Scar Akai = Akai, Amuro = Amuro

Aha, and Bourbon?

= the drink that Okiya might drink, and if I remember Jodie and James Black bought.

A word to play on Gosho's fourth wall, like a cliffhanger. Something that is used but will never be resolved to keep them coming back for more.

didn't Gin said burbon is on the train along with Vermouth?

then who is Vermouth?

[Chekhov MacGuffin]

Spoiler: some deductions

Yukiko for a few reasons:
The assumptions are...
Okiya is Akai
Scar Akai is one of the Black Org on the train - either Vermouth or Bourbon, with Vermouth being the primary candidate this time around, unlike previous meetings. I am assuming this is the case because Scar Akai talks to Masumi who would know Akai's real voice; only Vermouth can imitate voices, unlike Amuro who has been playing a mostly mute Scar Akai previously. (Say what you want about the different appearance of the scar or the outfit, because Gosho draws the scar with a lot of variance, and the dress-code for the train is formal.)

1: She is using a typical Yukiko disguise: a hat and hairstyle shift.
2: Yukiko would be sloppy enough to leave hair ties around her own house and lipstick on the glasses.
3: She mentioned something in passing to Scar Akai as she passed him in the hall despite being on enemy sides. Also, Scar Akai reacted with surprise. Kir wouldn't want to do this to blow her cover and her presence wasn't mentioned by the Org who should be keeping tabs on her. Fusae or Akai's mom have no motive to bother Scar Akai unnecessarily because they would not want to call attention to themselves. If this Scar Akai is Vermouth this time around, then Yukiko, who still should be upset over Vermouth lying about her past as Sharon and then faking her death might want to get a subtle dig in because her emotions and because her son is being threatened. Out of the protagonists, Yukiko would be the most likely to be able to notice Vermouth's tells in disguise and could pick out it was her. Also Yukiko knows that Vermouth knows Conan's identity, yet has not revealed it to the Org for her own reasons. Thus Yukiko knows it is safe to jab at Vermouth as long as she does it when Vermouth is alone (which she is) and doesn't lead her back to Okiya (meeting with Masumi prevents SA from following).
4: If Okiya contacted Haibara pretending to be Vermouth in order to force her out so he could move her to his "safe territory" then he could have gotten her number from Yukiko. Haibara contacted Yukiko back in the London case, so assuming she has the same number from back then, Yukiko can give Okiya her phone number. Neither Vermouth or Amuro know Haibara's phone number. Okiya appearing at the right location at time to intercept Haibara after driving her out doesn't seem like a coincidence either.
5: Okiya could have gotten suggestions from Yukiko for his original disguise.

Didn't Gin say Bourbon is on the train along with Vermouth? Then who is Vermouth?

The most popular theory right now is she is Scar Akai, with the idea that it has normally been Bourbon doing Scar Akai in the other cases prior to the train one.

[GinRei]

The most popular theory right now is she is Scar Akai, with the idea that it has normally been Bourbon doing Scar Akai in the other cases prior to the train one.

I think they're just poking at sstimson's "deduction" since it was full of holes and missing vital characters.

[doublemoonlight]

Spoiler: some deductions

Yukiko for a few reasons:
The assumptions are...
Okiya is Akai
Scar Akai is one of the Black Org on the train - either Vermouth or Bourbon, with Vermouth being the primary candidate this time around, unlike previous meetings. I am assuming this is the case because Scar Akai talks to Masumi who would know Akai's real voice; only Vermouth can imitate voices, unlike Amuro who has been playing a mostly mute Scar Akai previously. (Say what you want about the different appearance of the scar or the outfit, because Gosho draws the scar with a lot of variance, and the dress-code for the train is formal.)

1: She is using a typical Yukiko disguise: a hat and hairstyle shift.
2: Yukiko would be sloppy enough to leave hair ties around her own house and lipstick on the glasses.
3: She mentioned something in passing to Scar Akai as she passed him in the hall despite being on enemy sides. Also, Scar Akai reacted with surprise. Kir wouldn't want to do this to blow her cover and her presence wasn't mentioned by the Org who should be keeping tabs on her. Fusae or Akai's mom have no motive to bother Scar Akai unnecessarily because they would not want to call attention to themselves. If this Scar Akai is Vermouth this time around, then Yukiko, who still should be upset over Vermouth lying about her past as Sharon and then faking her death might want to get a subtle dig in because her emotions and because her son is being threatened. Out of the protagonists, Yukiko would be the most likely to be able to notice Vermouth's tells in disguise and could pick out it was her. Also Yukiko knows that Vermouth knows Conan's identity, yet has not revealed it to the Org for her own reasons. Thus Yukiko knows it is safe to jab at Vermouth as long as she does it when Vermouth is alone (which she is) and doesn't lead her back to Okiya (meeting with Masumi prevents SA from following).
4: If Okiya contacted Haibara pretending to be Vermouth in order to force her out so he could move her to his "safe territory" then he could have gotten her number from Yukiko. Haibara contacted Yukiko back in the London case, so assuming she has the same number from back then, Yukiko can give Okiya her phone number. Neither Vermouth or Amuro know Haibara's phone number. Okiya appearing at the right location at time to intercept Haibara after driving her out doesn't seem like a coincidence either.
5: Okiya could have gotten suggestions from Yukiko for his original disguise.

Didn't Gin say Bourbon is on the train along with Vermouth? Then who is Vermouth?

The most popular theory right now is she is Scar Akai, with the idea that it has normally been Bourbon doing Scar Akai in the other cases prior to the train one.

I know that I was asking Sstimson cause he seems to have no idea what he is talking about 

[Chekhov MacGuffin]

I know that I was asking Sstimson cause he seems to have no idea what he is talking about 

Sorry about that.

[tanteikun1412]

I voted for Elena, though at first I thought it was Fusae.
And the Hat Lady wasn't Vermouth because they have different phones.
Not Yukiko because what was the connection of Subaru and her.
Why Elena, because may be they were could be labmates, though he said that he was an engineer.
And talking to Scar Akai might be something about Akemi or Shiho.

[Kleene Onigiri]

I say it's Sonoci.

Strangely someone also voted "Okiya's middle aged mother after plastic surgery - 1 (5%)" :V *flees*

Oi!  >:( *chases after*

eek! D: *fears the evil lab-rats*

Voted Yukiko

[Stopwatch]

XD, the fashion sense argument is great .

@Chekhov: It's been shown in the NY case, that Yukiko can't tell Vermouth's disguises. I think it makes more sense that Okiya/Conan figured out 'cause she's the only known org disguise artist.
Also, I don't think SA's reaction is correct for someone who's disguise has just been blown and who has found out that Yukiko is around. With how Vermouth reacts to Conan, I think she still has some feelings for Yukiko so after the "OMP - she knows?!" freakout that would be a lot stronger than staring after ML a second, she'd be extremely worried for her.
And SA then going on to try to fool Sera seems a bit stupid if she thinks her cover is blown. ML could come back at any moment and it's not like SA can't get out of it. S/he could just put on a different voice and leave the cap and scar do the rest to prevent Sera from figuring it out, then figure out a way to contact Amuro to distract ML and try again later (from the 'promise' between them, I think Amuro already knows enough and should co-operate as he needs her for the entire SA stuff. She probably intends to get him killed later if possible anyway). But, SA doesn't do anything like that so I really doubt Vermouth's cover has been blown.

[canyoutakemeback]

I can understand why Yukiko is the most probable person to be the mystery lady but, if Okiya is Akai, then why would he risk the life of a normal civilian? Isn't the FBI's job to keep as many people safe as possible? And Okiya's disguise was already there before he entered Shinichi's house.. So there was absolutely no need for Yukiko to be there. Ans why would he need her? Akai is more of the 'silent' type and Yukiko is more of an impulsive person(like Conan). She could ruin everything and (by accident) expose him somehow.. There is no reason for Okiya to risk that.
( In my opinion, she's Akai's and Sera's mom. I have absolutely no proof of that or anything but Gosho wouldn't mention her for nothing, right? She had to appear one day.. )

[PT]

XD, the fashion sense argument is great .

@Chekhov: It's been shown in the NY case, that Yukiko can't tell Vermouth's disguises. I think it makes more sense that Okiya/Conan figured out 'cause she's the only known org disguise artist.
Also, I don't think SA's reaction is correct for someone who's disguise has just been blown and who has found out that Yukiko is around. With how Vermouth reacts to Conan, I think she still has some feelings for Yukiko so after the "OMP - she knows?!" freakout that would be a lot stronger than staring after ML a second, she'd be extremely worried for her.
And SA then going on to try to fool Sera seems a bit stupid if she thinks her cover is blown. ML could come back at any moment and it's not like SA can't get out of it. S/he could just put on a different voice and leave the cap and scar do the rest to prevent Sera from figuring it out, then figure out a way to contact Amuro to distract ML and try again later (from the 'promise' between them, I think Amuro already knows enough and should co-operate as he needs her for the entire SA stuff. She probably intends to get him killed later if possible anyway). But, SA doesn't do anything like that so I really doubt Vermouth's cover has been blown.

The thing is, though, Vermouth is an actress, too. She knows how to hide her surprise pretty darn well. So if, in fact, her cover was blown in a place where she didn't have a chance to do anything about it, I don't think she'd freak out too much. The minimal reaction Scar Akai gave was actually perfect for that.

And Scar Akai didn't confront Sera, Sera confronted Scar Akai, literally right after Mystery Lady disappeared, so not like there was time for SA/Vermouth to escape and change or anything. Vermouth had to play it off like nothing happened.

[Tenken]

Another FBI or CIA agent.

[zek]

Yukiko

[Dus]

I can understand why Yukiko is the most probable person to be the mystery lady but, if Okiya is Akai, then why would he risk the life of a normal civilian? Isn't the FBI's job to keep as many people safe as possible? And Okiya's disguise was already there before he entered Shinichi's house.. So there was absolutely no need for Yukiko to be there. Ans why would he need her? Akai is more of the 'silent' type and Yukiko is more of an impulsive person(like Conan). She could ruin everything and (by accident) expose him somehow.. There is no reason for Okiya to risk that.
( In my opinion, she's Akai's and Sera's mom. I have absolutely no proof of that or anything but Gosho wouldn't mention her for nothing, right? She had to appear one day.. )

Might be that they were afraid of Shuichi's cover being blown with Sera appearing so they brought her onboard to make a better disguise for him. Or maybe she was the one to make the disguise anyway. At least that would explain why she stayed with him in her house (or maybe she just loves a man who can cook). The question remains why he would bring her on the train. Maybe because she can apparently detect Vermouth when in disguise, that's something that might come in handy.