wiring a collector pickup

Solder or crimp on a small ring connector to the Center rail pickup wire. Attach it with the mounting screw for the roller assembly.

I looked up your loco on the Lionel parts website.  The correct roller assembly ("Collector" in Lionel Speak) is this one, but it is no longer available:

You may be able to mount your pickup rollers with some improvising.  Typically you will need the correct top and bottom plastic insulators for your pickup.  Place the screw through the ring connector, then the roller bracket, and then bottom insulator and screw the assembly into the top insulator mounted on the truck.  

If you know the part # for your pickup rollers, you may be able to find the insulators for it.  But if not, here are insulators that appear to fit your pickup rollers:

Ordering page from Lionel.  Parts #11 and #12.  

Since you are Frankensteining this together, you will need to figure out how to mount the insulators and roller assemblies to your trucks and keep the metal parts insulated from the metal trucks.  The best scenario is if the trucks already have at least the top insulator.

Bob

I normally crimp a ring terminal on the wire and put it under the screw for the pickup.  If that isn't really working for you, you can also scuff the side of the fixed part of the pickup assembly and solder the wire to it, I've done that a bunch of times as well.

My favorite pickup for this job is the MTH BD-0000042, it's short arm allows it to fit between the axles on most tender trucks.

Here's a couple of tender pickup examples that I've done.  I normally make my mounting insulators from either Styrene sheet or fiberglass.

Super thanks. I'm new to all of this. The pics and part no. are very helpful

another pickup question what collector will fit this tender truck