Well I saw someone suggesting to have a way to make your units walk faster and this is my idea, Railroad Tracks
Railroad Track
Price: The price is determined by the length of the track.
Features:
-Boosts your economy of the 2 cities where a railroad track is leading to.
-Units can travel faster from one city to another.
How to build:
1. Select the city you want the railroad track to begin at.
2. Click the orange hammer button
3. Select the railroad track
4. Select the city you want the railroad track to end.
5. Press the buy button (This is also where you see how much money it costs and the economical bonus it will give you.)