July Challenge - U - Underground, Overground

Wombling free,
The Wombles of Wimbledon, Common are we....

Confused?, you will be!

For this first of 2 days with the letter U we have an Underground train which is not only going Overground, but is also going over an Overground train, while the Overground train is going under the Underground one. Told you that you'd be confused!

Added in to the mix is an Unnecessary, Unneeded comma which Unpleasantry, Upsets the Unreal Untamed Utilitarian Urban Untidiness Upstarts.

I wonder if there are any Us left for tomorrows second U day?