I've accepted the task of adding lighting to a large number of
cabeese. About 50 or so. Most of them are brass and have the
relatively common shouldered truck screw that has a spring that
holds the truck against the bolster. And most of them have an
electrical situation where one side of the track and the trucks
and the frame and the body of the caboose are all tied to each
And since these are primarily brass - the trucks on them are
selected/detailed for that particular caboose class for that RR.
Furthermore they are also, in general, sprung trucks where the
truck side frame moves with respect to the truck bolster.
Finally the trucks are set up to have both trucks electrically
the same ... both truck's wheelsets having the same side 'hot'.
I do -not- have to achieve dead solid electrical pickup. I'll
be using a circuit that only needs to see the power every once
in a while and will drive the LEDs I'll use for the lighting
So my challenge is that I need to get the power from the other
rail (actually from both rails - but in most cases one of them
is "already done").
One way to do this would be to put some kind of wiper on the
insulated wheel that either wipes on the back of the wheel or
on the wheel tread. I'm concerned that doing this will affect
or compromise the action of the truck side-frame and bolster.
Another way would be to replace the metal truck screw with a
fiber screw and put in an insulating washer between the truck
and the body - thus electrically isolating the truck from the
rest of the model and allowing reversing the trucks so that
each truck picks up from one track. The challenge here is
that the existing truck screw is almost always one of those
shouldered screws where the larger diameter goes completely
thru the truck bolster and the shoulder bottoms out on the
body. Nobody that I know makes shouldered screws out of fiber.
So I'd have to figure out how to put some kind of 'sleeve'
on a standard size fiber screw - and that sleeve would have
to be electrically dead as well.
Any body have any other ideas? Any body have any strong
preferences for/against any particular method above?
thanks ... Jim
I faced the same problem on one of my brass cabooses. The bolster on this
caboose is composed of a turned brass center post with a pair of
fabricated/decorative brass bolster side pieces. The turned bolster center
post was screwed to the bottom of the floor from inside. My solution was to
first remove and discard the fabricated bolster side pieces (you don't want
them touching the center post and you can't see them anyway). I then
redrilled the screw hole for the center post so that it was larger that the
diameter of the bolster center post by about a 1/16". A piece of .040"
styrene about 3/4" square was mounted inside the caboose body over this
enlarged hole and the bolster center post attached to the styrene with a
screw from the top/inside. The result is that the bolster center post is no
longer touching the brass floor and is isolated. A small brass solder tab
was positioned under the screw holding the bolster center post to the
styrene...the wire to the lighting circuit attaches to this tab thus making
a connection to the truck and one rail. Because the bolster center post is
now screwed to the styrene rather than the floor, that end of the caboose
will ride lower by the thickness of the floor but that difference is so
small I ignored it. If it is a problem, you could insert a styrene washer
equal to the thickness of the floor between the top of the bolster center
post and the styrene.
The only critical step is to align the bolster center post in the enlarged
hole so that it doesn't touch the brass floor. I did this by screwing the
bolster center post to the styrene (with the solder tab in place) and then
placing the piece of styrene on the floor with the center post in the
enlarged hole. I clamped the styrene in position and then turned the floor
over to check that the center post was correctly aligned with the hole. Once
everything was correct, I bonded the styrene to the floor with CA. I think I
reinforced this bond with a pair of screws up into the styrene from below
the floor along the centerline of the car.
There are probably easier ways to solve this problem but this was the best I
could come up with...
Jim Betz wrote:
Here are some photos of how I provide electrical
pickup for non-motive power equipment. It is O
scale, but the techniques are scale-independent.
I am a big believer in all-wheel pickup and so
leave the trucks hot to the frame of the car,
leaving just the insulated side in need of
wiring into the carbody.
Any questions please holler.