Collecting -- and collecting information 20

The end of an investigative trail.
(Click on images to enlarge)

Sometimes you can only research something so far -- and then you reach a dead end. I had found two Japanese tinplate toy signs. They seemed to go together -- were they part of a set?

I eventually found the answer when I saw such a set for sale. It had six signs and six vehicles (see Collecting -- and collecting information 15). Then I found another set with railroad-related signs and a small train. It was obviously made by the same anonymous Japanese company.

So I had a better idea of the extent of the product line, but since all the items I found were loose, no indication as to who the manufacturer was.

Then I ran across this offering of new old stock. It's a slightly different set of signs, and this time there are trucks rather than cars included.

Now I know a little bit more. The signs were shipped flat, which explains why most of the ones I found were poorly bent and didn't stand up very well.

I now know there were at least four different sets offered:

1) Railroad set
   Signs - semaphore, dwarf signal, crossbuck RR crossing sign, hexagonal RR crossing sing
   Vehicles - locomotive and two passenger cars

2) Traffic Control set 1
   Signs - Yellow stop sign, Slippery when wet, School zone sign
   Vehicles - Cement truck, gas truck, milk truck

3) Traffic Control set 3
   Signs - hexagonal RR crossing sign, keep right, speed limit 50
   Vehicles - red, green and blue cars

4) Traffic Control set 4
   Signs - hexagonal RR, keep right, stop ahead
   Vehicles - red, green and blue cars

What I still don't know is who. There are no markings or brands on either the packaging or the contents that provide any answer.

So it seems I've reached a dead end. I'll keep looking, of course -- there may be other sets out there. But I'm not optimistic about discovering their origin.