I was on Caltrain recently and noticed that the Braille for many of the signs must either have typos, or uses some other version of Braille than I've heard of. How can I tell? Well, the places where the same letter occurs have different symbols in each place. The picture above is of a similar sign, and I notice that it also has errors, though different from ones on Caltrain's signs.
Is this sort of thing common with Braille transliterations? Or perhaps this is Grade 2 Braille?