Re: Type C/UP trucks

Posted by Phil Wiborg on Apr 25, 2020; 3:06am
URL: http://c-sng-discussion-forum.254.s1.nabble.com/Type-C-UP-trucks-tp15497p15566.html

Upon further review, I want to correct a couple of things on my 2 field
notes previously posted.  The items will probably not affect your HOn3
models, but will likely affect anyone trying to understand the truck.

First, on field-note 1, in the lower left, it looks like I wrote
"spring hangers", when I meant "swing hangers"; also the upper
"spring pad" is really the "upper swing pad" - the upper bearing
for the swing hanger (not sketched).  The actual swing hanger's dimensions
are given, w/o a sketch: 3/4" thick material x 5 1/2" wide, with a 2 1/2"
slot.  It's length I did not attempt to measure.  It could be estimated
from the note by the truck side frame sketch.

The lower swing bearing bars are sketched by the un-named drawing above
and to the right of the spring plank: the part dimensioned as 2x3x17 1/2".
The things that look like slots on 14 3/8 centers are actually
about 2" dia. turnings about 7/8" long that are the lower bearings
for the swing hangers.  The swing hangers of course go through slots
in the transoms and upper pads, and short keys or pins hold everything
together.  The transoms, spring plank, and bolster (also un-named) are
of wood, the lower swing bearing and (again un-named) side bearing
# 7307 are steel or iron.  The sketched 1/2 x 4 strap (hopefully) holds
the truck together, should it derail.  The pair are shown centered
on the bolster center, but of course bolted to the transoms.

This all "goes without saying" to someone that understands
swing-motion trucks.

Next, The note in the upper right of the same page: the spring
pad clusters don't attach to the transoms, but to the swing plank and
the swing bolster

On field note page 2, I don't know why I crossed out two dimensions and
increased them by 1/2".  I didn't use them when I made the "after" journal
box and lid drawing.  The long note in the lower left of this drawing
was a note to myself about another truck (which I visited and measured
a year later) and can be ignored.

I hope this makes understanding my sketches a little easier.

Phil