Jointed Rail's signals are numbered similarly.
Type 04 = Absolute
Type 05 = Permissive.
There's a small bar where the signal name is supposed to go. Permissive signals mean the train engineer or conductor must ask permission to pass the signal, however, in Trainz the AI will pass the signal without getting in trouble. With these signals, they can allow multiple trains to occupy a block. A real train driver seeing a flashing yellow will prepare to slow down in preparation for a solid yellow signal which indicates the next signal will be red. This used to work in Trainz but it no longer does; we only get solid yellows now.
Type 06 = Diverging signal
Type 06d = Advance signal. This has a small bar under the signal heads too like a permissive signal.
Type 08 = Interlocking - has 3 signal heads.
Auran/N3V added in a couple more signals in the series that Jointed Rail never adopted - Type 01 and Type 02.
Type 01 = Absolute
Type 02 = A 3-headed Advance signal.
I don't remember if a Type 03 signal exists or what that is. It may have existed in the olden days but I can't remember.
The signal rules used by N3V are similar to the NORAC rulebook used by the northeastern railroads such as RDG, NYC, NH, EL, etc., and still used today by NS and CSX. Given the flexibility of Trainz, various content creators have created custom signals based on regional and worldwide differences.
Canada, for example has their own signaling system that's different than those used in the US, and this is the same within the US where there's custom rules for greater Chicago and the western region, meaning west of Chicago, where the system is different than that and in the east. To make matters worse, there are custom adaptations within the base rules adopted by various transit agencies and regional railroads.
