Machine Men

Machine Men, a phrase that to my knowledge was coined or at least popularized by another personal hero of mine, Charlie Chaplin in his famous speech at the end of the movie "The Great Dictator". The song seems to suggest that industrialization will eventually over-take humanity.

Reminds me of the cybermen xD

I think this song is about Bruce's feelings about Iron Maiden at the time. He had left on acrimonious terms a few years previously and around the time of Chemical Wedding's release Maiden were at the lowest point in their history, having just released the poorly received Virtual XI album.

There are lots of references which could be interpreted as criticisms of the Iron Maiden "Machine":

Let the children make their noise See the monsters in their metal cages

"Metal cages" may refer to the perceived limited scope of Maiden's music, which apparently frustrated Dickinson. One of the reasons he left was that many of the song ideas he brought to the band were rejected in favour of more "Maiden sounding" material.

Turn the lights down in your soul Cut the power to your heart

Could refer to how he felt creatively stifled at the end of his first stint in Maiden.

See the carcass in its dying rages

Points to the fact that Iron Maiden were at the lowest point in their career, with poor sales of their previous and new albums, a poorly attended tour, and rumours abounding that the band were on the verge of splitting up.

Machine men, iron bites the dust

Perhaps the clearest indication he is singing about Iron Maiden.

What bitter vampire made you this? Gave you life with it's deathly kiss Ground your limbs to bloody stew Made a new machine of you

This could be referring to Bruce's replacement in Maiden, Blaze Bailey, and how they fared under his vocal leadership.

Turned a nightmare into day Sucks your breath, takes your life away Beating harder through your veins Someone else's cold remains...

"Sucks your breath, takes your life away" and "Someone else's cold remains..." could be interpreted as criticism of Blaze's vocal talents and his inability to perform the Iron Maiden classics to the standard that Bruce did.

Iron - in the soul (repeated)

Was perhaps a nod to the fact that Bruce still felt a strong affiliation to Maiden despite everything that had happened in the preceding years. Coincidentally (or perhaps not), he rejoined Maiden the year after this came out.