| Word | Description |
|---|---|
| Fast Clock | Used by many operators during operating sessions to simulate prototypical operations. Traditionally, this clock is on the wall and is set up to run at a faster than normal rate so that you can "get in a full day's work on the railroad in a fraction of the time." |
| Forward Trim | A scaling factor applied to all speed step power values in a speed table for the forward direction of the loco. |
| Free-mo or FREMO | Free-mo is an American group that has developed the idea that a set of standards focusing mainly on module endplates enables faithful modeling of prototype trackplans and operations in a modular environment. The length and track configuration of a Free-mo module or module set is up to the modeler. Free-mo takes the boredom out of running trains monotonously around a double or even a triple track mainline. With Free-mo, less is more. Free-mo operates like a permanent or sectional layout but still retains its modularity (Free-mo is actually more modular then existing double track modules). Free-mo layouts are operated with a single track mainline in a point to loop, loop to loop, or point to point. Layout sizes can vary to any size conceivable. FREMO (Freundeskreis Europäischer Modellbahner) is a German group with goals and standards similar to Free-mo in the USA. |
| Function Cell | A group of electronic components within a stationary decoder that controls the logic for a pair of decoder inputs and outputs. Used to operate local routes. |
| Function Control | This is the range of functions that a Throttle can control |
| Functions, Decoder | Function leads are extra decoder wires that you can connect to any device on the loco that you want to control from the hand held or other input device such as a computer. These can be used for locomotive lighting, sound units, smoke units, and other locomotive animation tasks. |
| FX Functions | Specially designed functions (available on Digitrax FX series decoders) that let you set up lights on your loco to simulate Mars lights, Gyra lights, ditch lights, rotating beacons, single or double pulse strobes, flashing lights, random firebox flicker and more. CV's 49-63 are used to set up these special light effects. |