Mr. Motorman plugged into a US outlet

I recall trying to tell you this in a previous thread:

I do want a Mr. Motorman but I would have to get a Transformer to plug it into.

Wrong. The Li-Po version (AA size receiver) uses USB, like RC helicopter/quadcopter batteries. You would plug it into a USB port.

---

There's no such thing as a Mr. Motorman unit that uses mains electricity like standard (and 12V/9V LEGO) model trains. Also, it's not a AA battery, but a receiver that replaces a AA battery in a drive unit and contains its own (non-replaceable) rechargeable battery.