The color light signals in the Atlantic tunnels do not follow NORAC rules. NORAC color light signals can display a more wide variety of aspects than the ones in the Atlantic tunnels. Not to say that they cannot be changed, but currently, they do not adhere to NORAC rules.
How do they not adhere to NORAC rules?? What colour aspect is displayed that does not match up with one of the 21 NORAC colour aspects? Since LIRR engineers need to follow NORAC colour aspects when traveling into Penn Station it does not make sense that the Atlantic Ave tunnel would not use the same colour aspects as the East River tunnel. Keep in mind that just because they do not display all the NORAC aspects does not mean they do not follow NORAC. Now of course they might only follow NORAC in aspect and not in rule, but I don't want to get that nitpicky.
Do the "automatic block" and "interlocking" color signals in the Atlantic Tunnel work like NYCT signals?
Oh goodness gracious no. The LIRR uses speed signaling, not that lame-o route signaling used on the NYCS. The whole railroad vs. transit signaling talk is too long for this thread so I'll refer you to this website here
http://broadway.pennsyrr.com/Rail/Signal/ The crux of the differance is that railroad trains can't stop on a dime like transit vehicles can.
Also, what exactly is a low home signal?
These are also called pot or dwarf signals. In areas of close clearances, dense trackwork or low speed/density operations dwarf signals are employed. These are cheaper than high signals, but also provide less visability. With the exception of the B&O, dwarf signals tend to display a different set of aspects than their taller breatheren. For example G/R on a high signal is CLEAR. G/R on a dwarf is only SLOW CLEAR. Y on a high signal is APPROACH while Y on a dwarf is RESTRICTING.
