I'm not sure what you mean.
All of the factory installed (or add-on) LED lighting boards for Kato models are designed to operate from 0-12 volts.
The LEDs themselves work on lower voltages, which depend on the color (chemistry to be accurate) of the LED itself. Red and amber LEDs operate at around 2 volts and white at around 3 volts. But you should never run LEDs without series-connected current limiting resistors and using s slightly higher voltage (that is if you want them to last a long time).