Lionel 258 E-Unit Wiring

A photo of the situation would help. Post war, pre war? Not sure what you have but motor field wire might need on outside top finger of drum.

Some late prewar motors were reversing field instead of reversing brush. Is the bottom brush holder grounded thru the mounting screw?

There is a consistency in e-unit wiring that is the same whether it is the field or brushes that are being reversed.

The motor is two magnets, one rotating and the other fixed.  One of those magnets is the field and the other is the armature, which gets electric current from the brushes.

Now consider that drawing of the E-unit contacts.  The contact on the right is always connected to power.  The left contact is wired to one side of the magnet not reversed by the e-unit (usually the field for Lionel).    Note that which outside contact is which connection doesn't matter - reverse them and the result will be the same.

The two middle contacts go to the magnet that has its current reversed (usually the brushes on the armature for Lionel).

You can swap the words armature and field and still have the same reversing effect.,  The e-unit is simply a DPDT switch that changes the direction through either the armature or the field - doesn't matter which.  It's really that simple.

There are dozens of Lionel and American flyer wiring diagrams for different locomotive, but all of them follow the logic that I've just described.  The Lionel diagrams relate the connections to different physical locations on the engine, but the logic of the connections is always the same.

The same logic holds for Lionel pendulum reverse units and manual switches and for the sometimes appalling AF units.

Malcolm Laughlin

Thanks all for your advice.  What I found works is the wire from the bottom center finger of the e-unit goes to the field winding and one of the wires from the left or center fingers goes to the motor brush.