I appreciate the effort but you lost me in the first line. Rails? Volts? In the the equation V = I R, I assume that V is volts but what is the other stuff?
google is a wonderful tool:
Ohm's Law is V = IR, where V = voltage, I = current, and R = resistance. Ohm's Law allows you to determine characteristics of a circuit, such as how much current is flowing through it, if you know the voltage of the battery in the circuit and how much resistance is in the circuit.