I think the part that really creeps me out is that they put throbbing cock-veins on the smokestack. Why?

Those aren't cock-veins.... that's just what they do to express anger or other excited emotions... in this case though it's probably arousal :P

So where's the nosebleed?

picword: Anime

You'd think there would be one.

picword: forbidden love

I wish I could read that...

I can kinda translate it for you...

トーマス！トーマス！
Thomas! Thomas!
俺は前からお前のことを。。。！！
From before I've (thought about) you
な。。何をするんだジェームズ！
Wha... what are you doing, James!
ちょっと連結するだけだよォ！
Just a little connection ;D
ああああああああ！れんけつ！！
AAAAAAAH connection?!
ジェームズ！
JAMES!
ずん！
(sound effect)
俺も前からお前のことを！！
I've also (thought about) you from before!!
どうだ！俺の馬かは
What about it?! (The 2nd sentence is probably saying he doesn't believe this but I'm not 100% sure.)
おおおお！夢の三重連！！
OOOOH! My dream triple connection!

picword: karin confused

Thank you.

I think.

Of course we need it. Why wouldn't we need it?

How... how do trains fuck?

picword: weirderons

According to the text, it's a "connection" lol

Rule 34 in action. God help us.

picword: Internets