[Since the car is used on an out-and-back train that doesn't turn,
markers will be installed on both ends. A DCC function-only decoder
will be used to turn on the appropriate end markers for the train's
direction.]
Here is a view of the parts used on the insulated side. The length of the wiper was truncated when the image was processed. Note the phenolic stand-off that raises the wiper above the channel section of the truck bolster. Also note the 0-80 plastic screw that keeps everything insulated from the truck frame. Wire lugs like that shown are available from me; they are sized for either 0-80 or 2-56 screws, and will accommodate up to 24 gauge wire. With them the wiring is a lot cleaner in appearance and much easier to work with if something has to be maintained or tweaked.
Note in the first photo that the wiper
tab has been bent 90 degrees and that the wiper has been trimmed so
that it clears the insulating bushing on the wheel center.
This photo shows the parts used on the unisulated side of the truck.
Note that the screw is now brass. A separate wiper is used, one for
each axle, because that is simpler. Note in the first photo that the
wipers have been bent into a "gull wing" (anybody remember the F4U
Corsair?) shape in order to clear the channel.
This photo shows wipers installed on the insulated side of of the rear truck on a Key F A unit. The brasss wiper mount stand-off (see parts photo below) is mounted in a plastic strip that has been machined to fit the truck/bolster joint. That is how this wiper is insulated from the truck frame.
Two wire runs come off the post. One run goes inside the body where it
joins the lead from the front truck before being joined to the DCC
decoder. The other wire run goes to a connector behind the unit. A
similar connector comes forward from the front truck on the B unit.
Thus the "electrical sides" of the A and B unit are joined together
(left side to left side, etc.) to give 16 wheel pickup (8 wheels per
side.)
This view shows the wiper assembly separated from the truck. Several pieces of paper were inserted under the assembly to make things more visible. The dark pointed area through which one wire run passes is where the three pieces of paper meet. The main purpose of this photo is to show you the sequence of assembly of the wiper, and how the plastic block was machined for a compatible fit with the sideframe and bolster.