I own a company that does, amongst other things, sell 3D printers and runs a 3D printing hub (and this isn't the main reason I'm posting this - I find the idea quite intriguing even if we don't end up being involved in bringing it to life). If there's interest enough (both by the brilliant folks beh...

Why don't you use smart inserters/intelligent chests to unload the empty barrels from the train and use a circuit network condition on the inserters so they will only work if there are less than, say, 1000 empty barrels in the chests?

Blimey. I am filled with speechless amazement.

Wow!

Having played a few dozen hours, I absolutely love the game... and am particularly intrigued by the circuit-related possibilities.

What do you think... it should be possible to implement a working Tetris game in Factorio, right?