Maybe I was not clear. I'm author of one of them (the middle one), its dat is like this:
obj=roadsign
waytype=road
is_private=1
...etc...
All three of them work perfectly in simutrans 100. The problem is that toll gates (in version 111) have the same dat file - is_private=1, but completely different behavior. Thus the old private road signs behave like toll gates - you can set which players can go through, but the images are just wrong, as prissi said - 4 images - 2 for closed, 2 for open, but the old signs have 4 images for 4 directions. So forget about using these old signs in new versions. Their graphics have to be replaced by gate.