[ S x.y, RP x.y, FAQ x.y, where x. and y are numbers - example: S2.15,
F1.7, RP 5.11 ]
S = Standard. All Free-mo modules and participants
must conform to the requirement/standard stated.
RP = Recommended Practice. These are procedures or
specifications which are strongly encouraged for maximal reliability or
FAQ = Frequently Asked Question/Answers which
explain the reasoning behind a particular Standard or Recommended
S1.1 The objective of the Free-mo Standard is to
provide a platform for prototype modeling in a flexible, modular
environment. Free-mo modules not only provide track to operate realistic
models, but also emphasize realistic, plausible scenery, realistic,
reliable trackwork and operations. Free-Mo was designed to and continues
to push the envelope of modular model railroading to new heights. It goes
beyond the traditional NMRA closed-loop set-up in creating a truly
universal"free-form" modular design that is operations oriented and
heavily influenced by prototype railroading.
S1.2 Interoperability: The Free-mo Standard is a collection of requirements
for building scale model railroad modules that can work together with
little effort, even when they have never been assembled together before.
The beauty of theFree-mo standard is that it allows builders to replicate
any freelance or prototype trackplan within your modules boundaries, yet
can be combined for maximal interoperability with other Free-mo modules.
S1.3 A Free-mo module is a free-form module that conforms to
the Free-mo Standard as outlined below. (FAQ
S1.3.1A Free-mo module can be any length
and the endplates can be at any angle to each other.
S1.3.2A Free-mo module can
be one section or a set of two or more sections that form a module.
Free-mo Standard governs the ends of the module and basic track
requirements. Most Free-mo modules have two ends, but modules can have
one, two, three, or more ends. (FAQ
S1.5 Free-mo modules fall into three basic categories:
S1.5.1 Mainline - Mainline modules represent
Mainline rights-of-way. Mainline modules are designed with large
radius curves and minimal grades.
S1.5.2 Branchline -
. Branchline modules represent Branchline rights-of-way. Branchline
modules can have smaller radius curves and steeper grades than
S1.5.3 Mini-mo - Mini-modules (mini-mos) have
endplates that are narrower than the standard width endplate. With
this in mind, a mini-mo can be Mainline or Branchline module,
single-track or double-track. (S1.6)
S1.6 Mini-mo type modules are intended to be a Free-mo
subset and not replace or exclude an equivalent length standard module.
Full width modules are generally more stable and should be used wherever
S2.1 Endplates shall be 3/4" plywood or equivalent
(birch plywood works well) to provide sufficient strength for
clamping to adjacent modules. (FAQ 2.1, RP2.1.1)
RP 2.1.1 Avoid Dimensional Pine Lumber for your frame work. It
has a tendency to warp and "cup" with age, throwing off track alignment.
It has also been found that plywood (birch plywood works well) warps and
twists less than dimension lumber (3/4 inch pine boards). (FAQ
Single-track endplates shall be 24 inches wide by 6 inches tall.
S2.3 Double-track endplates shall be 26 inches
wide by 6 inches tall.
S2.4 Roadbed shall be 1/4 inch cork or equivalent
on 1/2 inch plywood or equivalent. Foam tops are acceptable if braced
to prevent sagging or flexing.
S2.5 The nominal and minimum height of the the railhead,
at the end plate, is 50 inches from the floor. (FAQ
S2.6 On modules with grades, the elevation of the
high end shall be some multiple of 3/4 inch above low end.
S2.7 The maximum height of railhead , at the end
plate, is 62 inches from the floor.
S2.8 The module (set) shall have at least four
legs and stand on its own.
S2.9 Legs shall have continuous
adjustment of plus or minus 1 inch (screw type foot).
S2.10 The bottoms of the legs shall have rubber
tip or equivalent floor protection.
S2.11 Modules may be used with operators and spectators on
either or both sides. (FAQ
S2.12 There are no special benchwork construction
requirements for Mainline Modules in excess of the standards specified
above (S2.1 through S2.11).
S3.1 Modules shall use Flex or hand-laid track.
S3.2 The centerline of the all tracks shall be 4
inches or more from the sides of the module at all times. (FAQ
S3.3 On a Single-track module, the through track shall be
centered on the 24-inch endplate. (FAQ
S3.4 On Double-track modules, the two through track
be spaced precisely 2 inches apart and centered on the 26-inch endplate.
S3.5 Track on the through route must be perpendicular to the endplate for 6
inches from each end of the module.
S3.6 Track on the through route must be straight and level for 6 inches
from each end of the module.
RP3.6.1 The points of a turn out should not be
within 6" of the end of a module.
S3.7 Rail shall be cut off 1 inch away from module
end; ties and ballast shall be continued to the module end for good
appearance and matching with the adjacent module. Ties shall be notched
under the ends of the rails and to the module end, to clear bridge
rail joiners and provide freedom of adjustment for bridge rails. (FAQ
RP3.7.1 To enable DCC power districts, your
module must be able to accommodate insulated rail joiners at each
RP3.7.2 Free-mo printed circuit board tie plates
are recommended for ends. (F7.1)
RP3.7.3 Tie plates where the fitter rails go
over should be excavated slightly to permit fitter rails to
accommodate any vertical irregularity in track alignment between
S3.8 Turnouts shall be at least #6.
RP3.8.1Turnouts on the module through route
should be #8 or larger.
S3.9 There shall be a minimum of 12 inches of
straight track between reverse curves.
S3.10 Track on the through route of a Mainline
module must ALL be Code 83 nickel-silver rail without exception.
S3.11 Sidings, spurs and other tracks of a
Mainline Module may be
Code 83 or smaller, but shall be no less than Code 40.
S3.12 The Minimum permitted curve radius on a
through route of a Mainline Module is 42 inches. This includes through
track sidings and other tracks where through traffic will run. (RP
RP 3.12.1 While the minimum permitted radius of
curves on the through route of a Mainline module is 42 inches, 48 inch
and larger curves are preferred.
S3.13 Spacing between tracks on curves of a
Mainline Module shall allow for
long cars to operate without fouling each other; observe
S-8 Tack Centers for "Class Ia" equipment.
S3.14 Mainline maximum permitted grade on the
through route of a Mainline module is 2.0 percent (approximately 1/4
inch per foot). (FAQ
S3.15 Vertical curves on the through route of a
Mainline module shall be appropriate for
operation of contemporary long cars, see
NMRA Standards S-7
Standard S-7 Clearances
and the NMRA Gage, and
RP-11 Curvature and Rolling Stock.
S4.1 Wiring consists of 2 pairs of buss wires
(track buss and accessory buss) and a 6-conductor LocoNet
S4.2 Track and accessory buss wire shall be 18 AWG
S4.3 The LocoNet buss shall be telephone type 6-conductor cable.
S4.4 There shall be a 4 (or more) position
barrier strip under the module at each end for track and accessory
buss wire hook-up.
S4.5 All ends shall have a pair of 2-pin Jones
plugs, one male and one female (Cinch Part Number P-302-CCT and
S-302-CCT or equivalent) for the track buss. (FAQ
S4.6 All ends shall have a single, 2-pin trailer
plug (Radio Shack Part Number 270-026 or equivalent) for the accessory power.
S4.7 All ends shall have a surface mount "6
conductor 6 position" module jack (RJ12) mounted to the inside of
the endplate for the LocoNet Buss. .
S4.8 Through route wiring is as follows for Jones plugs
(must be facing module end for correct perspective): (FAQ
S4.8.1 Single-track -
- Male contact 2 right rail.
- Male contact 1 left rail.
- Female contact 2 left rail.
- Female contact 1 right rail.
S4.8.2 Double-track -
- Male contact 2 right rail.
- Male contact 1 left rail.
- Female contact 2 left rail.
- Female contact 1 right rail
RP 4.8.1 - On double track modules, to
facilitate optional train signaling/detection, separate feeders
are recommended for each track so that detection can discern a
train on track A or track B.
S4.9 Track feeder wire must be 24 AWG or larger,
but not longer than six inches to the track bus to avoid voltage loss.
S4.10 All turnout frogs shall be powered. Turnouts
shall not rely on switch points to power the frog.
S4.11 Accessory power shall be approximately 16 volts
AC or DCC. The buss is wired straight through. A bridge rectifier and
filtering capacitor may be used to convert AC or DCC signal to DC.
Applications that require AC or DCC signal may utilize power directly
from the buss. (FAQ
S4.12 Each module will have
one dual flush mount "6 conductor 6 position" modular jack (RJ12)
faceplate mounted on each exposed side of module, for throttles. (Digitrax UP-5 Throttle
Jack or equivalent)
RP4.12.1 For maximal convenience in areas
where operators congregate (such as yard modules) one or more
modules in these areas should have more than one set of throttle
jacks per side.
RP4.12.2 Each module sections should have a
dual flush mount "6 conductor 6 position" modular jack (RJ12)
faceplate mounted on each exposed side.
S4.13 All of the LocoNet connectors and associated
cables need to be connected together straight through (i.e. pin 1 - pin
1, pin 2 - pin 2, pin 3 - pin 3, etc. ...note standard telephone cables
are NOT wired straight through).
S4.14 To connect the DCC
buss between modules, a 2-foot
RJ12 to RJ12 type straight through cable is utilized.
S4.15 To connect a DCC booster to a module, There
are two connections that have to be made. (1) The LocoNet (2) The Track
S18.104.22.168 For the LocoNet, a 4 foot RJ12 to RJ12 type
straight through cable is utilized.
S22.214.171.124 For the Track Power, a 4 foot cable with one
female and one male 2 pin Jones plug on one end is used. It is plugged
between interfacing modules and connected to the output of the
S5.1 LocoNet compliant DCC and accessories are standard
for interoperability within and between Free-mo groups. For more information
about LocoNet Technical specifications consult the Digitrax website.
S5.2 For a given turnout, turnout controls must be on all
sides of the module or module section, excepting any endplates.
RP5.2.1 Turnout controls should be located on the fascia,
and not on the horizontal or vertical surfaces of your scenery.
S6.1 All benchwork shall be hidden by some form of scenery.
S6.2 General module fascia color shall complement
scenery and not draw attention from the scene.
S6.3 Scenery at the Free-mo standard end(s) shall have a
flat profile 3/8" below the top of the rail on the through route.
S6.4 The through route shall be ballasted Woodland Scenics Fine Light
Gray or equivalent,
S6.5 Standard rail color on the through route is Floquil/Polly-S Roof
Brown or equivalent.
RP6.5.1 Ballast on Through route is to be weathered
with a fine mist of thinned Floquil/Polly-S grimy black or equivalent.
Standards & Recommended Practices Revision History
Links to other resources
Standards & Recommended Practices FAQ Page
"A Gentle Guide to the Free-mo Standards" by Robert Slaughter