Houston N'Crowd proposes to
build
a series of modules to these TwinTRAK standards. Click
here to download the PDF version (Adobe Acrobat Reader required).
1. Frame sizes:
Lengths are in multiples of two feet,
with a
minimum size of 2’ X 2’ and a maximum of 4’ x 6’.
2. Height of track:
Normal track height is 40” above the
floor.
3. Track location:
The twiNTRAK main lines (yellow and
blue)
are set at 5” (Yellow Main) and 6-1/2” (Blue Main) from the
lengthwise
center of the module board on both.
4. Module electrical
interfaces:
We will use Molex connections (Radio
Shack part numbers 274-151 and 274-154) for the yellow, blue and white
(DC Supply, for accessories) cables. Be sure to solder the bus
wires to the Molex connectors, as merely crimping them may not maintain
adequate contact. The Molex connectors have one square side and
one peaked (like a roof) side. The outside rail is always
connected to the wire on the peaked side of the Molex connector.
The inside rail is always connected to the wire on the square side of
the connector. For the DC power wiring, the peaked side of the
Molex connector will be considered the positive (+) side of the cable.
The female Molex connector, part number 274-151, goes on the left hand
side (as viewed from the front) of the module and has about 20” of wire
dropped from the bottom of the module. The male connector, part
number 274-154, goes on the right hand side (as viewed from the front)
of the module and has a 6” drop. Each module has a 110v
multi-plug cord, with at least 15” of extra cord to make the connection
to the next module. The multi-plug unit should be placed on the
underside of the module, near the left end (when viewed from the front)
of the module. There are no special requirements for DCC
operation: NTRAK standards for wire size will suffice.
Though not a standard, the suitcase connectors sometimes used to
connect the track feed (22g solid wire) to each rail’s bus wire is the
Radio Shack #RS 64-3053, “Tap-In Squeeze Connector.”
5. Track size:
Code 80 is standard. Code 55 is
acceptable
so long as there are appropriate transitions to the end pieces made
(see
item 14).
6. Turnouts:
Peco turnouts are standard. All
turnouts
on the mains, passing tracks and interchange tracks will be number
8s.
Number 6 turnouts may be used in other sidings, yards, and branch
lines.
MicroEngineering and Atlas turnouts may only be used off the main and
passing
tracks.
7. Grades:
Grades of no more than 1.5% across a
dedicated
set of modules is recommended.
8. Scenery:
Any realistic scenery is permitted.
Round
down all ends of hills so the adjacent flat modules look
realistic.
Sets of theme modules are encouraged! Use buildings, hills,
tracks,
etc., to separate scenes on a module.
9. Skyboards:
Skyboards will be standard. They
will extend
12” above the module deck.
10. Junction and special
transition modules:
The smallest recommended size is 3’ X
4’.
No special design is recommended at this time.
11. Corner modules:
Standard corners do not apply to
twiNTRAK.
Bend Track style dog-bones may be placed at the end of each
layout.
If one chooses to build a standard NTRAK corner, the recommended size
is
3’ x 3’.
12. Offset modules:
Offsets are in one foot increments.
These
provide visual variety. Remember to consider
construction
of these in pairs, as the offset will need to be accounted for in a
“closed
loop” type of display layout. Observe all other standards.
13. Passing siding
modules:
Basic passing siding modules should be
incorporated
into a twiNTRAK layout. Two 4 foot modules will provide about a 7
foot passing siding.
14. Module legs:
To speed set up and tear down of the
layout,
special legs are used that differ from NTRAK standards. The legs
are made of 2” x 2” lumber and each is 38” long. One end is
machined
to fit easily into a 2” x 2” pocket on each corner of the module
frame.
The other end has an eyebolt (1/4-20 X 2-1/2”) for height
adjustment.
15. Module interface (joiner)
tracks:
Kato part number 20-050, 78mm-108mm
Expansion
Track, is used to connect mains from one module to the next. If
using
only Kato track, the module tracks must stop 1-7/8” from the end
of the module. The connector track then fits into the gap.
If using flex track, the Kato Snap Track Conversion Track, part number
20-045, may be used to transition from the flex track to the connector
track. In this case, the Kato Snap Track Conversion Track is
spaced
from 1-7/8” to 4-3/4” from the end of each module.
16. Optional module alignment
dowel:
Ray Byer will provide the club with a jig
to
allow placement of a 3/4” dowel in the center of the left end (when
viewed
from the front) frame member. This dowel will fit in a
complementary
3/4” hole drilled in the right end (when viewed from the front) frame
member
of the adjoining module.
17. Curve radius:
Minimum radius for all mainline tracks
(yellow
and blue) is 24”. Suggested minimum radius for all other tracks
is
18”.
18. Ballast:
The standard ballast will be Arizona Rock
&
Mineral Company (AZ R&M) #138-1, Southern Pacific Ballast. If
this material is unavailable, acceptable alternatives are AZ R&M
#105-1,
PRR, or other ballast batches that come close to these colors.
19. Track placement
review:
The mains are placed at 5” and 6-1/2”
from the
center of the board; Kato Snap Track Conversion Tracks are placed
1-7/8”
from the end of the module; 24” minimum mainline radius with proper
easements;
all adjoining tracks should have 1-1/2” center spacing; dedicated
module
sets may place the mains at other locations on the modules, so long as
the end modules of each set have the proper track spacing.
