A new Railway tunnel found under Metadata / Game Objects / Environment in CAW. You need Ambitions and to place the packages in both the mods/packages (Sims3 ) directory and in the "The Sims 3 Create a World Tool/ Packages" directory for the tunnel to show in your game. There is an earlier post explaining how to install items in CAW.
Importing packages into CAW
Railway open wagon for CAW
Railway crossing - flashing traffic light
End of track railway track for CAW
Diesel locomotive for CAW
Railway line crossing ramp for CAW
The farm 3. grain hopper and railway tracks for CAW