Free-mo Standards Frequently Asked Questions (FAQ)


1.0 Introduction

FAQ S1.1 I like everything except …

When you decide to join an organization that already has adopted a set of rules or standards, you, by the fact of freely deciding to join, accept those rules. If you didn’t like those rules (standards), then continue your search for a group, any kind of group – model railroad, civic, religious, whatever – whose rules you agree with.

As Free-mo has grown lots have people have asked this question. We are open to change, but a standard that changes too easily or fast cannot be followed. Many groups are following this standard and it works. When there has been a real need to change, it has changed.

When the Standards do change it will not be done lightly.  As a member you agree to change with the standards as they change and grow.

FAQ S1.3 What does free-form mean?

A Free-mo module can be any length and the endplates can be at any angle to each other. A Free-mo module can be one section or a set of two or more sections that forms a module. The Free-mo standards govern the ends of the module (or module set) and basic track requirements.

FAQ S1.4 How can a module have one or three ends?

If you build a loop module it will have only one end, a wye module will have three ends

FAQ S1.6 What is a Mini-mo

Mini-mo is used to describe a module that follow all Free-Mo Standards with a frew exceptions exceptions. Some people need special modules that are narower than a standard module for seting up at home. They do not have room for a full module and want to build something narower that follows the basic Free-mo Standards. Mini-mo modules are generally not used in public setups.

2.0 Frame and Legs

FAQ S2.1 Why not use Pine 1X6 lumber?

Pine dimensional lumber has a tendency to bend, warp and twist. Plywood tends to stay straighter over time. The use of Plywood over dimensional lumber will help keep your module flat straight and true. Standard plywood is made of 5 or 7 plies (layers). Cabinet quality Birch plywood or similar is made up of more and smaller plies, normally 11 or 14.  The more plies the stronger and more stable the plywood becomes.

FAQ S2.5 -Nominal and minimum rail height is 50 inches above the floor?

The nominal (noraml) value as measured from the top of the railhead to the floor is 50″. This is also the minimum, since Free-mo allows grades the max rail height at a Free-mo end is 62″. The ±1 inch adjustable feet are to deal with uneven floors. This allows a layout to be set at 50″ and kept level over a floor that may be dipping and bumping up to 1″.

What does Nominal Mean?

Maybe the confusion is with the word “nominal.” Mechanical engineers use it to mean the intended dimension. This dimension is then given tolerances. Two parts are never exactly the same. Tolerances allow slightly imperfect parts to actually fit together. So when is meant by the standard is the following:

  • The target minimum (or nominal) height of the rail is 50″ from the floor,
  • level track is more important than distance to the floor,
  • floors are not level,

The legs need to adjust to allow an actual rail height of 49″ to 51″ over the floor in the interest of keeping the track level.

FAQ S2.6

The Standard includes specifications for grade modules. You could be required to setup your module at a height above 50″ in increments of 3/4″. The original intent was that we be prepared to put 3/4″ shims under our modules to raise them up (again plus or minus 1″).

FAQ S2.7 The maximum height of railhead , at the end plate, is 62 inches from the floor, I thought Free-mo setup at 50″ from the floor?

The Standard includes specifications for grade modules. You could be required to setup your module at a height above 50″, in increments of 3/4″, up to 62″. Grade modules do not have to return to 50″, they can up and return to level at a height above 50″. The next module in the layout will need to be at this new height.  Technically a 61″ height is not compliant, but 61 1/4″ is.

FAQ S2.11 Can I put a backdrop on my module?

No! Your module has to be viewable from both sides and look “realistic” from both sides. Back drops are not allowed on Free-mo modules. Free-mo modules are also reversible and might be turned around in a setup. Free-mo modules do not have “fronts” and “backs”.

This precludes the use of sky-boards on a Free-mo module. Since sky-boards are usually placed on a non-viewing side, by being visible from both sides, a Free-mo module shouldn’t have a sky-board.

3.0 Track

FAQ S3.2 Why does the centerline of the all tracks have to be 4 inches or more from the edge of the module?

This is for two reasons.

  1. To protect models, if something was to happen and a train derails, we do not want the cars or engine to fall to the ground. It will be bad enough to have them on their sides.
  2. For scenic looks. It looks better if there is scenery between the track and the edge of the module.

FAQ S3.7 Why the 1 inch set back on the rail, why not take the track all the way to the edge of the modules?

Laying the rail to the edge of the module does have the advantage of allowing a nicer scenery transition to the end of the module, but there are some problems with the design.

  1. The first and most import to is that the rail at the edge of the module is frequently damaged in transport and set up, requiring immediate repair at set up time. This is not that easy to do and seldom results in the track looking or performing as well as it did before the repair.
  2. The second major problem is getting the tracks to properly align. Using a 2 inch piece of rail allows for slight mismatches to be smoothed out. Having the rail end at the module sometimes results in a kink (horizontal mis-match) or what we call a “ski jump” – a vertical mismatch of rails.

Both conditions are moderated by the addition of filler pieces.

FAQ RP3.7.2 What is a printed circuit board tie plate?

PCB Tie Plates are short length of Printer Circuit Board that is milled to look like scale ties. Some members uses them at the ends of modules to secure the rails. The PCB Tie Place can be secured to the module and the rail can be soldered to the PCB Tie Plate. PCB Tie plates are not the same thickness of the ties on all tyoes of track. PCB tie plates may need to be shimmed so that the tops of the PCB ties match the tops of the track ties.

FAQ S3.14 I do not understand how grades work?

A grade module will have 5 areas:

  1. a Free-mo End
  2. an Easement into the grade
  3. the Grade itself
  4. an Easement out of the grade
  5. a Free-mo End

1 and 5: the Free-mo Ends

These would meet all existing Free-mo end standards: 6″ long, straight, level, square at the end, rails stopping 1″ from the end, ties and ballast continuing up to the end. ANY other Free-mo module (flat, grade up, grade down) can be mated to these ends, at whatever height these ends start and finish at. You would still have the combined 12″ of straight and level track.

2 and 4: the Easements

Just as you don’t (shouldn’t) suddenly lurch into a curve without an easement between the straight track and the curve, you can’t (I say again, can’t) jump right into a grade from the level section. Imagine viewing your track from the side (a profile) – without the easement, your track would be 2 straight lines meeting at a hard angle. Going into an upwards grade, the wheels would risk jumping the track as they hit the angled track, the cars would uncouple as the one car is angling its coupler down below the level of the next car still on the level track, and just imagine the shaking of every car as it went into that angle. Coming back out of the curve, without an easement, the cars could bottom out, wheels leave the tracks, cars uncouple, etc. If a downwards grade, would be the same but in reverse. So you must have an easement in and out of a grade.

3: the Grade

As per Free-mo specs, you can have any grade, up to a max of 2% on a Mainline module,  or 1/4″ height change per foot. Nothing too fancy about it, as long as it follows any other normal track laying standards. Could even curve, again following Free-mo standards for max curve, and with an easement into the curve. (The grade easement areas could even curve too, meaning they’d be easing into the grade and easing into the curve.)

Only concern is meeting the 3/4″ incremental height requirements at the module’s ends. You can either take your grade (plus easements and Free-mo ends), and work out how long the module would need to be so that it would end up at one of the approved heights (50.75″, 51.5″, etc). Or, you decide how long a module you want to build, subtract the 6″ Free-mo ends and easement lengths, which then determines how steep a grade can fit within that space. You can stretch the grade through the entire length, or run your level sections longer than the min. 6″ required, or have an even longer/smoother easement. As long as the math works out so that at the end of it all, you meet the incremental 3/4″ specs.

Wrapping up the grade module

Using some general numbers for the lengths of the different sections and assuming a 2% grade. The lengths of the different section 1 to 5 would be:

  1. 6 inches flat and level
  2. 18 to 30 inches
  3. 36 inches for every 0.75 in lift
  4. 18 to 30 inches
  5. 6 inches flat and level

Using the low end of the scale for 2 and 4 of 18 inches. A module will take 24 inches on each end to get into the grade. This gives us the following:

Module length = lift:
7′ = 0.75″
10′ = 1.5″
13′ = 2.25″
16′ = 3″

I hope this puts the whole grade issue into perspective.

4.0 Wiring

FAQ S4.11  Don’t you mean AC & DC for the accessory buss?

Accessory bus can carry either an AC signal or a DCC signal. Many groups use a booster to power the accessory buss.

5.0 Control

6.0 Scenery

7.0 Glossary

8.0 Revision History