Workshop and Ironworks
You switched the hammer and the coin here
Clue 1: I am two things but one, different but the same.
Clue 2: Under most circumstances, the first thing must come before the second.
Clue 3:
Clue 4: Something related to one of the things produces .
Clue 5: The other thing is related to .
Railroad/Road
1. They serve the same purpose
2. You build roads and you build a railroad over it
3. Cities with a railroad connection to cap have boosted production
4. Roads create city connections = gold
5. Messenger of the Gods pantheon
6. Railroad technology unlocks Kremlin, unique wonder for Order
I was looking for just railroad, but I'll give you credit. I'll explain the clues the way I intended them:
1. Railroad tech and railroad improvement are different but have the same name.
2. You have to have researched the Railroad technology in order to build the railroad improvement.
3. Correct.
4. Correct.
5. Railroad tech is science related for obvious reasons.
6. Correct.