Jim,



You have the sollution. Of course adding wipers to both trucks you will have
a better contact but since you don't need a constant contact , insulate one
truck from the body will be easier ( I did this way ) .



Use the same screw , just make the washers to insulate the truck . If you
use a .020'' washer over the truck bolster , don't forget to remove .020''
on the chassis.



Is the same way the draw bars are insulated from the chassis on the brass
steam engines. If you need a sketch let me know.



My best



Marcelo Lordeiro

<http://www.mrcustom.com.br> www.mrcustom.com.br

<mailto:trens@...> trens@...

Tel.: +55 21 2273-2758



_____

De: STMFC@... [mailto:STMFC@...] Em nome de Jim Betz
Enviada em: quarta-feira, 19 de agosto de 2009 01:44
Para: STMFC@...
Assunto: [STMFC] Caboose Lighting





Hi,

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
other.
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
from that.

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