Hi everyone!

I decided to get back into pick-up artistry after having been in a long relationship, so I tried out some opening. I was sitting in a not-so-crowded train, where I positioned myself opposite two girls who where chatting with each other (opposite as in across the middle-path, so about 1.5metres from them, so too far to kino). They were constantly switching the language in which they were speaking, so I said "Hey, can I ask you something, 'cause I'm really intrigued. Why are you guys constantly switching your language?", spoken with a smile on my face and a joking tone. This elicited some giggles, and we chatted for a few minutes about learning different languages, studies and living abroad.

I was happy with how the conversation went: it was my goal to try out some opening, and it worked great. Feeling succesful, and not being prepared for what to do next, I reclined in my seat and got some papers out (I'm studying for my finals). One of the girls reengaged my attention by offering me some dessert she made (a clear IOI), upon which I reengaged the conversation for a bit, jokingly asking her how old the dessert is, as it was really crumbly, which elicited more laughs from both of them.

Anyway, after another 2 minutes or so, the conversation started slacking again, so I decided to leave it at that and focus back on my studies. Upon leaving the train, we smiled at each other and said goodbye.

I'm having mixed feeling about this. On the one hand, it feels great to see that I'm still able to do a cold approach, and I had fun chatting with them, which were my goals. On the other hand, I'm not sure how I could have proceeded to an eventual number-close with one of them. Should I have tried to engage them in a deeper conversation? Finding out which girl interests me more (one of them was better-looking than the other one, but I genuinely enjoy people's personalities as well) and focus on her? Moved over there and attempt some kino?

I could use some advice here, so thanks in advance

You played it perfect. Even with the silence gaps. Those gaps were good because it let the girl show ioi by reinitiating the convo. If you wanted to close, all you had to do was a false time constraint

"It was nice talking to you girls, are you on FB?"
"It was nice talking to you girls, wish we can continue the convo but this is my stop. You 2 seem like fun girls..What are you 2 gettin into tonight?" (Chance to setup double date with a wingman)

Hmm, yes, that might have worked. I should read a pick-up book again :p
I'm not sure though whether the established contact was good enough for them to want to give me their contact details. You think that could have been problematic?

Thanks for your analysis in any case, I'm going to use gaps more often I think.

I talked to a friend about it, and she suggested that if I wanted to close, I could have tried moving them over to my side ("Hey, you'll find this interesting I reckon", or "this could totally be me in a few years" and show them some of my studies), which would be a good compliance test, after which I could have done some light kino with the girl who sits next to me. I could then have built more rapport, and ended with some activity to invite her to. If she agrees, I get her number. If she doesn't, I say "Ah, what a shame, there goes my excuse to get your number ". What do you think?