You are right... in part. It is definitely à 946 Erie, type 1 in the Doyle catalog, p. 83. It has no. 7210 on the side, a green plastic generator, and the inscription ''NEW 5-29'', which would be the date (which one?) according to Doyle.
It has two 6 wheel trucks... but link couplers.
There are 2 holes at the bottom of the light housing, one a little larger than the other. I suppose the loose wire could go through the larger hole to be connected to the light socket. Could this socket come out in order to make this connexion ?
Sorry for your trouble.