Flex Track

Track systems that use fixed-length straights and curves (and other things) are called “sectional track” systems. In addition to the Kato Unitrack and Tomix FineTrack I’ve used and written about, there are a number of others. Some with integrated ballas molded to the track like those two, and others that are just ties and rail. But there’s also a more general approach to building track without the need to hand-lay it: flex track. Flex track consists of sections typically one yard (36” or 91.44 cm) or 1 meter (39.37”) in length with ties that are made so that the track can be bent into a curved shape.

It’s more complex to use flex track than sectional track, since you have to pay close attention to keeping curves smooth, and you need to fix the track in place. Some people use glue or caulking compound for this, others simply add granular ballast and glue it in place with white glue, trusting that to hold the track strongly enough for operation. The glued-ballast approach is easier to rework later, since white glue can be loosened with water. Some people also use nails, but these have a tendency of bend the ties and are probably best avoided.

Flex track still uses some sectional elements: switches, crossovers, and other complex track items, unless you want to hand-build those. And because each brand of flex track is slightly different in terms of rail thickness and height of railhead, as well as in appearance, usually it’s not a good idea to mix brands. There are certainly exceptions: in particular, mainline track is going to look different from sidings and branch lines anyway.

With flex track, the rail height is also more important, since there are multiple available with each scale. Rail height roughly matches prototype rail variations in weight, but in N-scale all rail is oversized (the smallest normally used, Code 55, is slightly larger than the heaviest North American rail used, and somewhat problematic to use). Normal sizes for N (and HO) are code 55, code 70, code 83 and code 100. Rail is also available in lighter codes (e.g., 40) from some suppliers, but this is very delicate. The “code” is actually the height of the rail in thousandths of an inche, code code 80 is 0.080” (or 2 mm) in height. Code 80 is probably the most popular with current modelers, although those seeking the best possible appearance will use code 55. Both Unitrack and FlexTrack use code 80 rail, although they mold the ties around it to make it look smaller.

Code 55 rail can be problematic for rolling stock with large “pizza cutter” wheel flanges typical of older-design models.

Some manufacturers of flex track sell adapter sections (short lengths of straight track) to change from one rail height (code) to another. These can allow a lesser size to be used on sidings and industrial track for a more realistic look.

Flex track can connect to sectional track (provided rail height and tie thickness are similar or can be adapted). Kato sells an adapter section, originally designed for use with FineTrack, but sold in the U.S. as an Atlas track adapter. However, simply shimming under the flex track with some styrene strips to get the rails to the same level will also work. It’s still important to match the rail code (e.g., 80 for most sectional track, although code 100 is also fairly common for sectional track).

Switches used with flex track, even when made by the same manufacturer, are essentially sectional track of the same height and shape of ties and rail. This makes them easiest to use, but often people mix brands (carefully) to get better-working switches with better-looking, or cheaper, flex track. Many modelers also use Kato’s double-crossover with flex track, as it’s economical and very reliable.

If you want a more general overview of both flex track and sectional track, with detail on use with Japanese train models, there’s a good one on this site.

Some common brands of Flex track used in N-scale are:

Note: I’m ignoring any flex track that doesn’t use nickle-silver rail, and so should you. Brass is for toy layouts.

- Reflects North American prototype look.
- Made in Code 80 and Code 55, both with wooden ties (code 80 in black, code 55 in brown).
- High molded spikes make code 55 problematic for larger wheel flanges.
- Switches available in multiple sizes:
-- code 55: #5, #7 and #10
-- Frogs are power-routed, but known to fail (many add a wire to avoid problems).

Micro Engineering:
- Reflects North American prototype look.
- The sell a “weathered” version with black rails (too dark for prototype appearance).
- Code 70, 55 and 40.
- Code 55 is available with concrete ties in addition to wooden ties.
- Ties are thicker than Atlas (in code 55 anyway).
- Code 70 and 55 have only one switch available: a #6 (code 40 has none).
-- Fast Tracks (handlaidtrack.com) sells jigs and parts so you can build your own switches for ME track.
- Requires more attention to produce a smooth curve than Atlas, but less prone to unbending before attachment.
- There’s a comparison of them to Atlas on this site.

- Said to reflect “European” appearance that looks good for Japanese track.
-- Uses 1:148 scale ties (British N), equivalent to Japanese commuter scale.
- Available in Code 80 and Code 55, both with either wood or concrete ties.
- Built to NEM standards, which are more tolerant of large flanges on code 55.
- But the 55 is really 80 recessed into ties, so it mates poorly to other code 55 rail.
- Does not unflex after being bent; requires more care when making curves.
- Switches available in three sizes with curving departure tracks, not straight.
-- Code 55: Small (12” R), Medium (18”R) and Broad (36” R) with #6 frogs.
-- Code 80: Small (9” R), Medium (18”R) and Broad (36” R).
-- Additional specialty switches (curved, double-crossover and single/double slip) are also available.
- Code 55 switches are electrified-frog designs, which need polarity-switching wiring.
- A good discussion of the track is available on this site.
- Parallel track spacing (for back-to-back switches or the double-crossover) is about 26-27mm.

- Note: Walthers is their exclusive U.S. dealer and doesn’t stock any N-scale, so this can be hard to impossible to find without importing. It is apparently available in both Europe and Australia.
-- Shinohara-branded track isn’t identical to Walthers-branded.
- Code 70 track and switches with wooden ties.
- Very broad line of switches including double-crossover, double-slip, and curved turnouts.

A comment on appearance:

If you’re modeling Japanese trains, as i do, none of these are going to be an exact match for the track used in Japan. While Peco may come close, it’s modeling standard gauge track in 1:148 scale. And while Japanese commuter trains models are in 1:150, they use 42” (1,067 mm) gauge track on the prototype, so larger and more widely spaced ties, relative to the rail spacing, will look more like the prototype, although nothing’s going to get away from the track itself being the wrong gauge (the models use standard 9mm N gauge). Thus, Atlas or Micro Engineering may, paradoxically, look more correct despite the scale problems. This is an area I need to look into more closely.

For Shinkansen, which are modeled in 1:160 scale, there’s still some ballasted track using mostly concrete ties (they also use synthetic ties), but most newer construction has the rail affixed to large concrete slabs set in rubber vibration-damping material without any loose ballast. This kind of “slab track” is also used in some non-Shinkansen construction, especially in stations. You could hand-build this by soldering rail to large pieces of circuit-board material, but nobody makes a flex or sectional track that matches it (well, some of the Japanese manufacturers have done specific elements this way, but it’s not common).