A model railroad needs model rails. The rails have to support and guide the train, just as on a real railroad. But in addition they must provide power to the train, at least in most forms of model railroading. Model rail is typically formed of a copper alloy called nickel-silver, although brass and steel have also been used. Nickel-silver has the advantage that it remains conductive when oxidized, and so it does not need to be scraped clean the way brass or steel rail does, but only to have dirt, oil, and dust removed periodically. Most modern track uses nickel-silver rail, and all track described here does unless noted otherwise.
The metal known as Nickel-Silver is actually an alloy of several metals, including copper, but despite the name, silver isn’t one of them. The name comes from the color, which is a shiny silver, readily distinguished from brass. The principal elements are copper (50% - 60%) and nickel (15% - 30%), although others including zinc, tin, iron and lead may be included in small quantities. According to Wikipedia, all modern formulas include a significant amount of zinc, and the most common formula is 60% copper, 20% nickel and 20% zinc.
Model rail is formed through an extrusion process, drawing nickel-silver wire through an aperture to shape the rail with a head, web and foot roughly similar to that of real rail.
As mentioned above, rail needs to be periodically cleaned to maintain proper function. Nickel-Silver rail requires less cleaning than other types, because its corroded form is still electrically conductive. But dirt is not, and needs to be removed. There are numerous cleaning compounds on the market, some better than others, but many leave an oily residue that traps dirt, leading to a need to do more cleaning. In many cases, all that’s really needed is a cotton pad moistened with alcohol, to remove any surface dirt and oil.
More stubborn dirt or heavy corrosion can be removed with an eraser block, of the kind sold for erasing pencil marks. A simple block of scrap wood can also be used in this manner. Abrasive cleaners, like the ubiquitous Bright Boy can be used, but these are excessive under most circumstances, and because they scratch the surface of the rail, providing places for dirt to attach, they can be somewhat counter-productive. Special cleaning cars, which are essentially cleaner-soaked cotton pads or abrasive pads on wheels are also available.
On prototype railroads, rail size is described in terms of weight per a standard unit of length, either the weight in kilograms of a meter of a single rail, or the weight in pounds of a yard. Rail of less than 100 lb/yd (roughly 50 kg/m) is used for Light Rail lines, and sidings that do not need to support heavy loads. Per wikipedia, most modern North American rail is produced at heavier weights, in the range of 112 lb/yd (55 kg/m) to 140 lb/yd (70 kg/m). The heaviest prototype rail was used by the Pennsylvania Railroad (PRR), which used 155 lb rail (77 kg/m) on its mainline track. European rail is typically lighter, under 60 kg/m (121 lb/yd). I don’t have weights for typical Japanese rail, although I’ve seen a non-authoritative source mention use of 120-lb/yd (60 kg/m) rail in more recent Japanese construction, and something closer to 100 lb/yd (50 - 55 kg/m) for older work.
In model railroading, rail size is typically described by its height in thousandths of an inch (even in countries that use the metric system). Code 100 rail is rail that is 100 / 1000ths of an inch (0.100”, or 2.5mm) in height. Most N-scale rail is code 80 (0.08” or 2.0mm), Code 70 (0.07” or 1.8mm) or Code 55 (0.055” or 1.4mm), although Code 40 (0.040” or 1.0 mm) is also available.
The NMRA Recommended Practice RP-15.1 describes (table 2) the code height to prototype weight equivalence. From this, it can be seen that all N-scale rail is oversized, with Code 55 rail being slightly larger than the heaviest mainline rail ever used. A more prototypically accurate size would be Code 45 for heavy mainline use, and Code 38 or below for lighter lines. However, rail that small would not work with the oversized flanges typically needed to keep wheels on track (even Code 55 can be problematic in that regard) and would be so flexible that it would be very difficult for it to reliably remain in gauge and support trains.
In Japanese N-scale, Code 80 rail is 12 scale inches in height, much larger than any real rail. Code 70 is 10.5 inches high, and equally unrealistic. Even Code 55 is 8.25” high, slightly higher than the 8 inch height of 155 lb/yd PRR mainline rail. Code 40 rail is 6 inches high, correct for 100 lb/yd AREA-standard rail, or rails up to 110 lb/yd by other standards. This would be a reasonable size for early twentieth-century non-mainline track, but is a bit light for modern applications other than light rail or lightly used branch lines.
For reliable operation, most modelers use Code 70 or larger rail for N-scale, as the oversize rail is only noticeable on very close viewing. Japanese models also tend to have large wheel flanges suited to the larger rail sizes, although this can vary.
Although nickel-silver is an alloy of copper, it is not quite as conductive as the form of copper used for wires. As a result, it has a higher resistance, and thus a greater amount of voltage is lost in a section of rail than would be in an equivalent length of wire. Dimension also plays a role here, with smaller rails losing more voltage than larger ones. For example, Allen Gartner’s excellent Wiring for DCC website lists the voltage drop for ten feet of Code 70 nickel-silver rail carrying one amp as 1.5 volts. For comparison, 14 gauge wire typically used as a track bus (power distribution wiring) loses less than 0.1 volt under the same conditions. For this reason, track needs to be connected to feeders fairly often, particularly as amperages rise or rail size shrinks. A usual rule of thumb is to have a feeder at least every six feet (two meters), although you can certainly build working railroads with wider spacing between feeders.
Model Railway track consists of the rail itself, the ties to which the rail is attached, the roadbed on which the ties are placed, the ballast that surrounds the ties and which is sometimes used to hold them in place, and the subroadbed which supports all of this. Subroadbed is typically a structural part of the layout, often plywood on extruded insulation foam. Roadbed is often a thin (1/8”) layer of cork, which can help to absorb vibration and thus reduce noise from running trains. Ballast may be crushed stone or similar materials glued in place after the track is installed, or it may be molded along with the ties out of plastic. And the ties themselves may be plastic or wood.
Track is sold either as separate rail, which would normally be attached to wooden ties glued to the roadbed, as sections of flexible track (“flex track”) with attached rail typically a yard or meter in length, or as short sections of track designed to be connected by metal clips known as rail joiners. This latter kind is called sectional track, and there are many separate varieties of it available.
Kato makes a line of sectional track with an integrated plastic ballast and tie structure, which are attached to other sections by a proprietary type of rail joiner called a Unijoiner. Unitrack is noted for its high quality of manufacture, rail that is very easy to keep clean, and the ability to be repeatedly taken apart and reassembled without loss of function, which makes it suitable for temporary table-top or floor layouts. However, over time and repeated use, Unijoiners will become less effective, and voltage loss between sections of track will increase.
Tomix makes a similar sectional track system, which is liked by hobbyists for its more prototypical appearance and greater variety of curves and type of track switches. Finetrack is harder to find, typically needing to be ordered from Japan (but see the Suppliers page), and does not stand up as well to long-term use for temporary layouts. The rail joiners used are similar to ordinary sectional track joiners.
Other Sectional Track
There are several other kinds of sectional track, by companies such as Bachman, Atlas, Peco and others. Depending on the manufacturer these may be ties and rail intended to be used with separate ballast, or integrated systems more similar to the Kato and Tomix systems. Most of these manufacturers also make flex track, increasing the variety of track plans that can be made.
Flex track is simply a length of rail with attached plastic ties, which are connected to each other below the track, but only on alternating sides, allowing the track to be bent into a curve by moving the outer ends of alternate ties away from each other. Flex track is typically connected to other flex track, or to sectional track, using the same simple track joiner clips. Further, flex track ties may be made to resemble either wooden ties or newer concrete ties (most sectional track is only made to resemble wooden ties).
Peco Code 55
There are a number of manufacturers of flex track, but one of the more popular ones is Peco. I’ve had them recommended by other modelers. And despite it being a British brand that’s styled to look more correct on British 1:148 N-scale, my local (U.S.) hobby store tells me its their most popular brand. One reason is that it’s built to European NEM standards, which are more forgiving of oversized wheel flanges on older trains, so the more realistic-looking code 55 track can be used with more trains than code 55 track from other manufacturers. It’s also well-made and apparently easy to work with.
Nickle-silver rail, which is actually a copper alloy with no silver in it, comes from the factory in a bright chrome color. Real prototype rail is a color that varies from a dark gray to a dark rust red, with only the top of the rail being shiny. Lightly-used rail rusts, so sidings and branch lines are often rust-red. Heavily-used rail tends to get any loose rust vibrated off it and thus is a more gray color. But rail, ties and ballast where trains brake frequently will often be dark rust red from all the metal shed from the wheels and brake shoes. And there can be other local variations. For example sharp curves often have devices that oil the sides of passing wheels to reduce rail wear, and this colors track and ballast black for hundreds of feet beyond the oiling equipment.
Many how-to discussions suggest airbrushing rail and ties a rust color, then wiping off the top of the rail with a thinner-soaked cloth before it can fully dry. I used this technique on my old HO layout, although I put down masking tape to avoid painting the ties since I didn’t want those to look rusty. You could do the same thing with a nearly-black gray, and ties would look more prototypical, avoiding the need to mask.
Today you can also get special paint markers to color the side of the rail, and this works better for sectional track like Kato that has pre-molded ballast. There are also weathering solutions you can paint on the rail by hand, but that seems like too much work so I’ve experience of them. You can also buy pre-weathered rail, but I find the color of that tends to be too black for my tastes.