Take a look at the following, posted originally by teledoc
Lionel E-units Prewar & Postwar info
I thought this would be a good addition to this link for Repair/Restoration. Speaking of E units, whether they be Pre or Post war items, the only major difference for a particular use, is in the length of wire from the contact fingers, so that they will be long enough to attach to the critical points of the motor. The basic design of the E units hasn't changed, only the lever location of FRONT or BACK mounted, or if the lever is UPWARD or DOWNWARD. The wire length is the only thing that makes a specific E unit compatible to a specific motor. Typically the E unit needs cleaning/repairing/rebuilding, so the wire length shouldn't be an issue, if replacement parts are going to be used. I did some searching on the Prewar versions of which all have the Upward levers.
The forward facing lever (away from the field coil) are the 1661E-5; 1668E-36; & 226E-35
The inward facing lever (toward the field coil) are the 259E-25; 260E-72; & 262E-10
A. 1661E-5 used on 229, 1664,1664E, 1681E, 1688E, 1689E
B. 1668E-36 used on 1662, 63, 64 (1940), 1666, 1666E, 1668E, 1684, 1688
C. 226E-35 used on 224, 224E, 225, 225E, 226, 226E
D. 259E-025 used on 259,259E, 264, 264E, 265, 265E
E. 260E-72 used on 250, 250E, 255E, 263, 263E
F. 262E-10 used on 238, 238E, 249, 249E, 262E
The supply of Prewar E units from dealers is very slim, but by substituting a Postwar E unit, of the same basic design as far as the lever location, there a few choices that can be made. The most common substitution for the FORWARD LEVER is the Postwar 100-25, which many Postwar locos used. The INWARD LEVER has 3 options available, with only difference of wire length, which are Postwar 100-8, 100-11, 2332M-10, all of the same design, different wire lengths.
The 100-8 was used on the #520 ;
The 100-11 was used on the #44,45,204,205,208,209,210,216,217,218,220,224,226 .
The 2332M-10 was only used on #2332
By using this information, you can come up with needy replacement using a Postwar unit, and just making the necessary adjusting to wires.
by teledoc posted 8/14/2015
swede