Object to Follow Path

Hello all!

I’m all new to 3D drawing and animation. Just started 2 days ago!
I’m trying to build my first creation in Blender.

I watched the video on how to create the underground subway scene by Andrew Price.

In my project; I added a cylinder from which I erased one half and extruded the ends to represent a tunnel / hallway. I then added an array modifier to make it longer.
Then I added a circle path and made the cylinder to follow it with the curve modifier.

What happens is that the cylinder follows the path, but it just pivots on itself so that the flat face which represents the ground faces the inside of the circle / path instead of facing the bottom…

Any suggestions?