Any idea what brand/model/year this is?

Sakai.

Yup, it's a post-war, Japanese, Sakai crossing signal. A number of years ago, I wrote a short article about the whole line, for the TCA Quarterly. There are quite a few variations and types, including two- and three-lamp block signals, a crossing gate, a semaphore signal, and this grade crossing signal. They also made similar items in (approx) H0 scale.

There's a relay in the base. The signal does not operate prototypically. It came with a red and a green lamp. The relay is a two-state latching device. A pulse from an insulated section sets the relay in the "green" position, and the next pulse sets the relay in the "red" position. In other words, even though the signal looks like a grade crossing signal, it operates like a block signal.

Lost in translation......

that looks to be in really good condition for being in the ground.

Thanks for the info guys!

It's in not-very-good condition.  I had to put the buzzer piece on top of the crossing piece and push the pole into the base to take the picture....nothing holding the whole thing together!  It's pretty much crumbling a bit at a time, and rust pieces keep falling off.

I'm amazed that it was in the ground for a while.  The house's previous owner had kids (1990-95) and they may have lost it outside back then...couldn't have survived in the ground since the 40's or 50's!

Great info that I can pass on to our neighbor!