Calgary Free-mo

Free-form modular railroading

The Calgary Free-mo Standards and Practices

Calgary Free-mo conforms to the Free-mo standards published on, with local variations and recommended practices which enhance our public profile and make setups and problem diagnosis easier, but do not affect compatibility or interoperability.

The major differences are:

Those who operate in official Free-mo meets will be able to set up at the standard 50" rail height.

Besides the basic interoperability of Free-mo, we have checklists for locomotives and rolling stock to ensure smooth operation, and a setup checklist to help avoid the “oops” factor at shows.

All of these are described in the following sections. A glossary of some terms is found at the end of these descriptions.


The main purpose of Calgary Free-mo is to provide a place to operate finely detailed HO scale standard gauge models in a realistic fashion. Operating trains is the important aspect of meets, so the layout setup does not follow the traditional "endless circle" format of modular layouts. Instead it follows a "free-form" configuration that does not readily lend itself to continuous running; trains originate from one point on the layout, traverse it, and then terminate at the other end (or back at the starting point). This format results in modules that are viewed from both sides, and that are designed to be reversible (rotated 180 degrees).

This type of operation requires end points, typically in the form of stub end yards or reverse loops. A layout may then take on the form of an "out-and-back" or a "point-to-point". Other more complex formats are possible if "junction" modules are built; for example a wye module could allow a branch line operation.

Between the end points of the layout are modules which carry one or two main lines from one end to the other. Large modules may be assembled from small, easily transportable "sections" to create a large layout feature; for example a passing siding long enough for a full-length train could be created as a multi-section module.

To date, we have constructed numerous double-track main line modules, primarily to facilitate public operations where frequent trains are desirable. We have also built a large number of double-to-single transition modules and a number of single track mainline modules.


Recommended practices are designed to make our setups more realistic/ easier/ better presented, but individual module builders may implement them or not as they prefer; they have no effect on the interoperability required for a setup, although some (eg signalling) may affect the setup plan.


This is the only mandatory standards variation for participation in most Calgary Free-mo setups. We normally operate at 42" rail height, rather than the 50" rail height in the official standard. We have found that at public shows, this significantly enhances the ability of the public (especially the younger members, who we want to infect with the virus) to see and appreciate the setup. For operations at 50" height, members will have various solutions – alternative leg sets, adjustable height legs, etc, so that compatibility with standard Free-mo is maintained.


Fascia Colour:

The official standard does not specify a fascia colour. We have chosen to paint the fascia Mayan Green (Home Depot/ Behr colour, they change the formula from year to year but e-mail us for the currently available mix). This gives a consistent professional appearance at shows.

Scenery Base Colour:

Scenery should be prepared with a base earth colour so that when bits of finished scenery fall off, it looks like dirt and not pink foam. Behr Dried Bark (flat) is the main colour used by our members, but any suitable colour will do.


The official standard does not specify a skirt or colour. We have chosen to use grey cloth skirting, again for a professional appearance at shows, and also to hide the immense amount of stuff that we invariably put under our modules. Because of the difficulty in getting a consistent source of material, the grey colour used varies somewhat; come see us to find out the current source for best match.


We recommend the use of good quality plywood and the avoidance of dimensional lumber, for environmental stability reasons. When planning a module, transportability needs to be carefully considered; if you cannot get a module to a setup, it does not exist. Modules should be sturdy enough to withstand frequent moves. Coffins or transport cages are recommended for protection during transport.


Track must be to NMRA standards and compliant with the Free-mo specifications. Perpendicularity to the endplates, exact spacing of dual main lines at the endplates, and flatness across the module – avoiding “ski jumps” - are essential. Calgary Free-mo members currently do not have any modules with main line grades.


Scenery should depict realistic, commonly found rail-oriented scenes. Scenery (especially tunnels and bridges) must allow hand-cleaning of all tracks using a track eraser type cleaner or alcohol soaked rag. Materials and techniques are user choice. Backdrops are not used in setups.

The Free-mo standard Floquil rail colour is no longer available. However, painting the rails a suitable colour enhances realism significantly.



We are gradually moving to a signalled system. To this end we recommend wiring such that sensing of trains can be easily installed, basically by having a module local branch feed off the main track bus for each main line track on which a current sensing system can be installed. See the Wiring Recommend Practice for the wiring implications. Signals are not installed on most modules; some members have short one foot single and double track “Signal Mos” with signal heads which provide great flexibility in setting block boundaries, the only requirement being that all intervening modules should have sensing installed. Our signalling system is provided by Signal Logic Systems ( This system interoperates with the California Free-mo signalling system but provides additional realism in signal performance. Where signalling is installed, Ethernet cables for connection of the sensing units to adjacent modules will be required.


The figure below illustrates our recommended wiring practices.

Wire Colours:

Wire colours are user preference; the preceding illustration shows the Calgary Free-mo preferred colours which aid in fault finding.

Since the modules are reversible in setups, the end chosen as reference does not matter.


“Fun Runs”:

A Fun Run is basically a private setup for our own pleasure, at some convenient location, and the guidelines are pretty relaxed. The setup is planned, but changes can occur at the last moment. Modules should be mechanically and electrically complete, but the run can be used as a venue for checking out new or modified modules to ensure wiring and trackwork is smooth, normally a good idea before scenery is applied. Glitches are accepted as bugs are worked out, part of the process of maturing a module. Operations are flexible and usually well into the night. There is usually an associated pot luck dinner or BBQ. A good time shall be had by all.

Public Displays:

At a public display or show there is a significantly different emphasis: paying customers want to see smooth continuous operation in a well presented example of the modeller’s art. The show is planned out and committed months ahead, and the only acceptable excuse for not showing up as planned is that you are dead. Preference is given to scenicked modules (although one or two interesting “in process” modules can spark conversations with the public). Operators are scheduled to ensure a continuous flow of trains from show start to shut down, and participating members can expect to spend several hours of each show day operating. We engage people in conversation, and it is a good opportunity to recruit new members.

Shows normally distribute profits to the participating groups based on a number of factors including size, quality, distance travelled, and audience engagement. Groups also get points for volunteering in other show functions. Shows provide the major source of funds for us, as well as an opportunity to run trains.

When operating at any setup, normal practice is to:

  1. Maintain a two-module distance between consists;
  2. Throw any switches back to mainline once switching is completed;
  3. Maintain an open yard for others to build consists; and
  4. Use set-up tables while building or removing trains, and then place storage boxes underneath to maintain space for others.


Calgary Free-mo currently owns the following modules and equipment:



Standard interface main line modules built to a common physical design, with a special keystone, form a loop. Modules are usable as standard Free-mo modules in other locations.


A keystone and any combination of ten loop modules form a loop. Group members own loop modules; Group or individuals can own keystone modules.


Module tops are cut to the precise shape necessary to maintain interchangeability using a template and a top-guided router. End plates are Free-mo double-track standard. Track arrangement is at user discretion provided it meets Free-mo Main Line standards.

Variant loop modules can be double or triple the single size, with (if desired) internal segment boundaries and interfaces. This can provide more flexibility for track arrangement and scenery.

Keystones may have different physical and track arrangements so long as they interface to the ten loop modules correctly, have a standard Free-mo interface on all three track crossings, and meet Free-mo Main Line standards.

A Keystone could also be used as a junction.


The Keystone has standard single track buses at each interface. Because the modules are in a loop, the two tracks must be independently auto-reversible; this requires completely separate track buses for each track, and a corresponding four pole PowerPole connector on each end of the loop modules. The reversing section of the loop can be between any two module boundaries, but should be at least as long as the longest train. A dual auto-reverser takes the single Track Power Bus at the entrance to the reversing district and provides two independent reversing feeds, one to the inner and one to the outer track. Each Keystone should have a dual solid-state switching auto-reverser set for high sensitivity to minimize power interruptions causing sound decoder resets.

For use as a normal Free-mo module other than in the reversing section of the loop, including those in the physical loop but not in the reversing section, the dual track buses need to be connected with a 2-to-1 connector at one end only to connect both tracks to the normal Free-mo track bus. Each Pyle module should have one of these.

Pyle Loop modules can also be signaled per normal wiring practice.

Accessory Bus and LocoNet are fed through the loop as with normal practice, with breaks at some point within the module loop so that electrical loops are not created.


Checklists help ensure that nothing is forgotten and there will be no (well fewer) “Ooops” at a setup. Some are for reliable operation within an owner’s trains; some facilitate “interchange” when we are running an operating session. If the reasoning for any is not clear, ask us “How do we know that?”

Locomotives and Rolling Stock



These amplify the definitions in the Free-mo standard. They reflect module–level descriptions; setup-level definitions are described subsequently.