ForceFlow the 1 ohm 1/2 watt resistor and the 2 #89 bulbs are the voltage drops in the circuit. The 330 ohm resistor is the warming resistor.
The power is constantly flowing through the bulbs and the warming resistor back to ground. The resistance is high enough to not let the bulbs glow but keeps the filaments warm. When the transistor fires the current goes to the least amount of resistance (1 ohm resistor) and lights the bulbs.