Coal Mine is crazy strong, and has anti-synergy with everything including itself. At best, it's like a non-interactive Pirate Ship. At worst, it actively discourages all players from buying fun cards.
It's way strong with cheap cantrips, makes +Buy cards bad, and is a pretty self-contained strategy by itself. Playing Big Coal Mine is more or less just a better Big Money that can compete on Colonies and Dukes. Probably not desirable?
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Conductor is really confusing to read thanks to it's nested conditionals. All else aside, that has to go.
I don't think there's anything inherently wrong with this attack, but it's not really that compelling either. It's sort of an odd combo--a weak Montebank mixed with a Cutpurse? I'm not sure it merits adding a new fat-free Curse card to the game. On that note, you would really need 10/20/30 copies of it if you want it to scale at all evenly in multiplayer.
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Funicular is really powerful! Neat and simple concept, but might need some power tweaking. It could cost 5 as written and I'd still buy several. Keep in mind that at +5 cards it becomes really easy to draw your whole deck and then some, getting you those Treasure right back. Just have a few villages around and it's off to the races.
Consider Council Room, for comparison.
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Handcar is political and scales like crazy with number of players. On the whole though, Copper-trashing cantrip isn't really compelling, especially when--as written--it has occasional "crap I don't have coppers in my hand but there are some in my deck, should I play this?" AP.
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Junkyard feels weak, even for a non-terminal $2 cost. It just feels like a raw deal, as it's rare to actually have the surplus needed to make this remotely valuable--again, even by $2 standards. It's especially awkward early game, when you can't play it after your Woodcutter or Herbalist.
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I think Repairs is going to be a lot more narrow than you might expect; on so many boards it's just not going to have an important use. A good $2 option helps it a lot, but in general there isn't much use for it outside of fringe cases like Peddler. Non-terminality isn't enough to make it better than Remodel, which isn't exactly the strongest $4 in the universe.
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Steam Engine is slick, I love it.
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Manifest confuses me. So it's a Reaction to an attack that does nothing but gives you $2 after jumping through a couple of hoops? Oh, or +2 cards, I see. That's still not very compelling, it doesn't compare favorably to Moat or Silver. The only thing working for Manifest is fringe interactions with Treasures, Black Market style.
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Depot Village is interesting, hmm. Not sure how fun it would be to play, but the value of it is interesting.
I'd be curious to see direct comparisons with Mining Village. It would go great with trashers almost like a Haven alternative, and might even be a really wacky combo with Baron. (I'd want to play that and see.)
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Bandits is really high variance, even more than Thief. (Which is saying something...) The steeper cost and higher late-game benefit makes it scale even more badly across number of players. Personally I wouldn't investigate this direction much further.
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So uh, Caboose is crazy good. You said you nerfed it, but it's still amazing. Free Golds! None of that Hoard Duchy/Estate-buying nonsense, these suckers come with Havens and Villages! The +Buy lets it combo with itself, which is probably good and fun... but only makes the power level issues worse. Try higher costs?