For Lionel questions you might do better in the Toy Trains forum
I have some old Lionel and a couple on newer switches, they do not need seperate power, they are track powered. You should have a three wire switch control, depending on the model of the switch (age) either the center post or one of the outside posts will be a common, the other two are direction. If the control says straight and it's turned, switch the wires.
Good luck,