1 Scales and Gauges

The words scale and gauge seem at first to be used interchangeably in model railways, but their meanings are different. Scale is the model's measurement as a proportion to the original, while gauge is the measurement between the two running rails of the track.

At first, model railways were not to scale. Manufacturers and hobbyists soon arrived at de facto standards for interchangeability, such as gauge, but trains were only a rough approximation to the real thing. See NEM and NMRA. Official scales for the various gauges were soon drawn up, but the scales were not at first at all rigidly followed, and were not necessarily correctly proportioned for the rail gauge chosen. O (zero) gauge trains, for instance, operate on track that is too widely spaced, while the British OO and N standards operate on track that is significantly too narrow. Most of the commercial scales also have standards that include wheel flanges that are too deep, wheel treads that are too wide, rail tracks that are too large and speeds that are too high.

Later on, groups of modellers became dissatisfied with these inaccuracies, and developed finescale standards in which everything is correctly scaled. These are used by dedicated modellers but have not generally spread to mass-produced equipment.

The most common scales and gauges in Europe and the USA are:

Name	Scale	Gauge in mm	Comments
Wide gauge	1:26.59 or 1:28.25	53.975	Called Standard Gauge by Lionel, who trademarked the name. Other manufacturers used the same gauge and called it Wide Gauge. Not widely produced after 1940. Gauge 2 using track of gauge 2" (50.8mm) was one of the standard model gauges in 1909.
16mm scale	1:19.05	32	This scale was first developed in the UK in the 1950s to depict 2 foot narrow gauge prototypes utilising 32mm or "O gauge" track and wheels, but really took off in popularity during the 1960s and 70s. Originally, it was mostly used as an indoor modelling scale, but has also developed as a popular scale for garden railways of narrow gauge prototypes. Some manufacturers that produce models depicting North American 2 foot narrow gauge prototypes have also adopted this scale for use alongside the near-compatible Fn3 (15mm) scale on 45mm track already popular in the US. Both electric, battery and live steam propulsion is used to power model locomotives in this scale, and is supported by a growing range of commercially available ready-to-run models, kits and parts.
Fn3 scale	1:20.3	45	Similar to G Scale below, this scale also 45mm gauge track, and used for both indoor and garden railways of narrow gauge prototypes. The scale of 1:20.3 was developed to depict North American 3 foot gauge trains in exact proportion to their correct track gauge whilst using 45mm gauge model track. It equates to 15mm = 1 foot scale. Increasingly popular for both electric and live steam propulsion of model locomotives, with an ever growing range of commercially available ready-to-run models, kits and parts. Fn3 scale, together with G scale and ½" scale, are commonly and collectively referred to as "Large Scale" by many modellers.
G scale	1:22.5	45	Name derived from 'G'ross, which means "big" in German. G is generally used for garden railways of narrow gauge prototypes, and uses the same track gauge as Gauge 1 below. The scale of 1:22.5 scales the trains correctly for the European narrow gauge standard of 1 metre. The gauge 3 scale on gauge 1 track.
½" scale	1:24	45	Similar to G Scale above, this scale also 45mm gauge track, and generally used for both indoor and garden railways of narrow gauge prototypes. The scale of 1:24 is an attempt to model North American and UK 3 foot or 3 foot 6 inch gauge trains in better proportion to their modelled track gauge.
Gauge 1 or I scale 3/8" scale	1:32	45	This large scale, once rarely seen indoors in modern use but frequently used for modelling standard gauge trains outdoors, is making a come-back. The Japanese firm of Aster offers ready-to-run gas-fired livesteam models. Gauge 1 has seen something of a remarkable revival in recent years after decades of near extinction commercially, with a growing number of smaller UK manufacturers offering electricly powered locomotive and rolling stock kits and parts for (mostly) indoor layout use. Some manufacturers offer so-called Gauge 1 items in 1:30.48 scale (10mm = 1 foot) that also run on 45mm gauge track.
O scale	1:43.5 or 1:45 (Eur) 1:48 (US)	32	Name originally was '0' (zero), '1' through '6' were already in use for larger scales. In the US, this is frequently a 'toy train' scale rather than for exact scale modellers.
Proto:48	1:48	29.90	These are to the same scale as US O gauge but are accurate scale models in all dimensions including track and wheels.
ScaleSeven	1:43.5	33	Exact scale version of British O gauge.
S gauge	1:64	22.42	Originally called "H-1" because it was half the size of Gauge 1 (1:32), the "S" name is derived from 'S'ixty-fourth. In the US, American Flyer toy trains are to this scale, but it is also used for more precise modelling and supported by several manufacturers. In the UK, S scale modelling is largely the preserve of a dedicated few hand-building models or using a small number of available kits and parts, mostly depicting standard gauge prototypes but also narrow and broad gauge subjects too. The UK-based S Scale Model Railway Society is the oldest scale support society in the world, being first established in 1946. This scale is also popular in North America to depict 3 foot narrow gauge prototypes (using dedicated 14.28mm gauge track and known as "Sn3"), and elsewhere to depict the 3 foot 6 inches narrow gauge railways (using HO 16.5mm gauge track and known as "Sn3½") of South Africa, Australia and New Zealand.
OO gauge		16.5	This scale is today the most popular modelling scale in the UK, although it once had some following in the US (on 19mm gauge track) before WW2. OO or "Double-Oh", together with EM gauge and P4 standards are all to 4 mm scale as the scale is the same, but the track standards are incompatible. OO uses the same track as HO (16.5mm gauge), which is not correct for this slightly larger scale, but it is the most common British standard for ready-to-run trains. In Britain there exists The Double O Gauge Association to promote this scale. Narrow gauge modelling of 3 foot prototypes ("OOn3" on 12mm track) was once popular although now less so, but the depiction of approximately 2 foot or 2 foot 6 inch prototypes ("OO9" on 9mm track) has a greater following with a flourishing supply of kits and parts from many small UK-based suppliers.
EM gauge		18	EM gauge was an earlier attempt in the 1950s to improve the inaccuracies of OO gauge, with wider, more accurate track at 18 mm between the rails, but still narrower than the correct gauge. Many early finescale modellers in the UK used this standard and it is still in use (albeit with the gauge now slightly adjusted to 18.2mm), although P4 has superseded it for most. The UK-based EM Gauge Society exists to supports modellers of these standards.
P4 Standards		18.83	During the early 1960s a group of British modellers evolved a finescale standard at 4 mm to the foot with near exact scale track and wheels. This was later formalised by the founding of the Protofour Society which attempted to exercise strict control over the manufacture of specialised parts to these standards. A separate group, the Scalefour Society, was formed in the 1970s promoting an even finer exact scale standard called S4, but encouraged a wider group of manufacturers to support its aims. Later, in the 1980s, sanity prevailed and both societies merged, adopting the original P4 standards by which it continues to be known (and not S4), but encouraging a wide manufacturing base and retaining the society name of Scalefour. The "P" stands for "Proto[type]" and these standards are intended to be applied to any prototype gauge in 4mm scale, which for standard gauge track happens to work out at 18.83mm. P4 standards have also been used to depict narrow and broad gauge railways on a variety of model gauges. In the UK many kits include parts to enable them to be built to OO, EM or P4 gauges and there is a flourishing "cottage industry" of small business kit and parts suppliers. EM gauge was an earlier attempt to improve OO with the more realistic (but still inaccurate) gauge of 18 mm (later 18.2mm).
HO scale	1:87	16.5	This is the most popular model railway scale in the world (except in the United Kingdom). The name is derived from 'H'alf 'Zero', and the European NEM defines the scale as exactly 1:87, the US NMRA as 1:87.1 (3.5 mm : 1 ft). Not surprisingly, there is a vast selection of ready-to-run, kits and parts for locomotives, rolling stock and scenic items from many manufacturers depicting trains from all around the world. Narrow gauge modelling of North American 3 foot gauge ("HOn3" on dedicated 10.5mm track) and 2 foot gauge ("HOn30" - actually 30 inch gauge - on 9mm track), European metre gauge ("HOm" on 12mm track) and 750/760mm gauge ("HOe" on 9mm track) has become very popular. In Britain, HO was popular before WW2 but lost out to OO and it virtually disappeared from the modelling scene, except for those modelling European and North American prototypes. A few commercial models depicting British prototypes were manufactured during the 1970s (usually in error or ignorance by foreign firms), which, together with a few items suitable for conversion to British outline, prompted some modellers to revive British HO modelling in the 1980s, culminating with the establishment of the British 1:87 Scale Society in the mid-1990s. Today, British HO is making a modest come-back.
Proto:87	1:87	16.5	An alternative finescale standard for HO, with wheels and track that correspond with the prototype's, taking its lead from the establishment of P4 standards in the UK.
3mm scale	1:101.1	12 and 14.2	A UK version of TT introduced by the firm Tri-ang in the late 1950s (then known as "TT-3") and supported by several other firms offering kits and parts. Commercial production by Tri-ang petered out in the late 1960s, but "The 3mm Society" was established in 1965 and a dedicated membership has kept this UK scale alive. TT-3 was originally designed to run on TT's 12mm gauge track, but latterly the more accurate gauge of 14.125mm (popularly known as "14.2") has been adopted by some seeking more accuracy. Like the intermediate EM gauge standard in 4mm scale, some modellers in 3mm scale developed 13.5mm track gauge, but this has largely been superseded by 14.2mm gauge. Both 3 foot narrow gauge (using 9mm gauge track) and Irish 5 foot 3 inch broad gauge (using 15.76mm gauge track) are also modelled in 3mm scale in the UK.
TT scale	1:120	12	Name stands for 'Table Top' - no longer widely used but making a come-back. There is a small following in the US, and a large following in Germany, especially in the former DDR.
N scale	1:148	9	As with 1:160 N scale below, name derived from 'N'ine millimeter track gauge, but the scale is a slightly larger at 2 1/16th mm = 1 foot. Developed as a UK commercial version of N scale in the late 1960s, models are restricted to depicting UK prototypes. Although nominally to 1:148 scale, some manufacturers take liberties with exact scale to suit production limitations, but there is a growing choice of ready-to-run models available. A few commercial kits and parts to fit Z scale loco mechanisms and wheels where once offered by the UK firm Peco to enable narrow gauge prototypes to be modelled, but these are hard to find or are now discontinued.
2mm scale	1:152	9.42	British finescale standard, older than N scale, being first used as long ago as 1927 with photos and articles published in the model press. Became more popular in the 1950s, with The 2mm Scale Association established by 1960 to promote and support modellers in this tiny scale, and it remains very active in the UK to this day. In recent years the finer track and wheel standards of 2mm scale (but not the gauge) have also been adapted for use in 1:160 N scale (on 9mm gauge) in Europe and called "fiNe", and is supported by the FREMO modelling organisation. Since the 1950s, incredibly, 2mm scale has been used to depict narrow gauge prototypes on various track gauges down to 4mm, but almost everything has to be hand-made, unless some Z scale parts are used.
N scale	1:160	9	Name derived from 'N'ine millimeter; this is the second most popular scale worldwide. N scale developed by the German firm of Arnold Rapido in the early 1960s, and was rapidly adopted worldwide as the most popular small-scale modelling choice. In recent years, finer profile wheels and track have been developed by some manufacturers (although the gauge and standards have remained the same). Huge range of ready-to-run models available as well as supporting kits and parts. With the introduction of an even smaller Z scale in 1972, the modelling of narrower gauge prototypes has been possible using that scale's locomotive mechanisms, track and wheels. In North America the depiction of 3ft gauge railroads in N scale using Z scale track is known as "Nn3"; in Europe, metre gauge modelling in N scale is known as "Nm".
Z gauge	1:220	6.5	The smallest commercially available model railway scale, introduced by the German firm of Märklin in 1972 depicting German and other European prototypes. In North America the firm of Micro Trains and others has introduced a range US prototype models. On both continents, a growing range of kits and scenic accessories has become available to help increase its popularity. In Europe a few enterprising manufacturers have developed even smaller metre gauge models (but still in 1:220 scale) known as "Zm" on 4.5mm gauge track, in this smallest of commercial scales.

2 The Philosophy of Model Railways

( a simple, non-technical guide, avoiding 'railway jargon')

Whether it is a simple clockwork train on a circular track, or a huge detailed layout run to a timetable with historically accurate signals and train formations, the essence of a model railway is that it presents the appearance of a working railway. It is essentially the pursuance of this appearance which causes people to spend varying amounts of time and money creating a model railway, sometimes making it a lifetime’s project. Anyone intending to make a model railway, however, must sooner or later confront not the similarities between their model and the real thing, but the differences. Unless these differences are accepted and accommodated in some way, the model is unlikely to be successful or satisfying.

Generally speaking, the purpose of a model railway is to be interesting to see and to operate, whether the ‘interest’ depends on historical accuracy, fidelity to the appearance of the original, or complexity of operation. Those models which contain more detail, more track and rolling stock, are generally more interesting. But it is important to remember that this is not the purpose of a real railway. If the railway companies of the past could have implemented a ‘Star Trek’ method of transporting passengers and goods instantly from A to B they would quickly have abandoned the use of trains, which was always an expensive method of transport. They would never have used more locomotives or coaches than was essential to maintain their traffic, and certainly they would never have built and maintained ‘interesting’ and complex track formations, which were notoriously expensive, without first making every effort to simplify them.

There is another essential difference to be dealt with. Even the largest model railway cannot model an entire line, unless it be a cliff or miniature line. Most if not all interesting lines would ‘go off’ somewhere to connect with the rest of the system. Even a very large layout must compromise, therefore with the need to ‘disappear’ off the edge of the modelled world.

Many modellers begin with the urge to see trains running as soon as possible, and rush into the first type of layout that occurs to them. Many of them find too late that they have committed themselves to a design which is not going to interest them for long, or they see when halfway into construction that they would have been better to adopt a different plan, even to model a different railway altogether. Successful and satisfying layouts are almost always the result of a considerable amount of planning involving compromise and tradeoffs. This can be frustrating at first, though it can become an enjoyable pursuit in itself, but the results of a well-planned layout are usually well worth the time and effort involved.

The first stage in planning is to decide what sort of layout is wanted. All is not what it seems here, for though a large layout may seem more interesting to a beginner, it is likely to prove too exhausting in its construction and operation to be truly satisfying. On the other hand, someone who is determined to be historically accurate above all may spend an enormous amount of time in the construction of a layout which in reality had only three or four trains per day, using at the most two locomotives. It is therefore very important to decide first what one wants from a layout. Common themes include historical accuracy, detailed modelling, and operations. One popular approach is to choose a locale and a period in history, for example Virginia in the 1940s or New Mexico in the 1960s.

For many years the most popular form of layout was the ‘continuous run’, evolving from the simple ‘trainset’ or ‘toy train’ circuit of track. The advantage of this layout is that the trains do indeed run continuously, and a train can be seen running for a period of time not greatly reduced from that of a real train journey. It also avoids the need to have a ‘rest of the world’ located offstage somewhere. The disadvantage, however, is that it is most unrealistic. No real train appears again from the same direction after a few seconds! Modellers who really wish to see main line trains run for lengthy periods, however, may suspend their disbelief, or compromise with this aspect of the model, in the interests of getting what they want.

The other extreme from this type of layout is the ‘branch line terminus’, also known as a point-to-point line. The advantage of this layout is that while simple to operate and requiring few locomotives, it is realistic in operation. The trains arrive and depart like a real branch-line train. Much satisfaction can be gained from the inclusion of a small goods yard and the visit and shunting of the daily goods train. The disadvantage is that all the rolling stock must have an ‘elsewhere’ to go to, off the layout, representing the ‘rest of the system’. This is commonly known as a ‘fiddle yard’ where all traffic intended to run onto the layout is assembled by hand, and of course this requires extra space, often as much as the ‘real’ or modelled part of the layout. Another disadvantage is that the operation can become very unvaried after a while. Modellers whose urge to start a layout came from watching long expresses racing by will not find this very satisfying.

Many layouts follow a middle course, and model a stretch of line with ‘rest of the world’ at both ends. This is both realistic and satisfying to watch. Here too, though, there are disadvantages: two ‘fiddle yards’ are required, one at each end, and the amount of rolling stock required to represent a realistic selection of traffic is considerable. The modeller with time and space to spare will, however, find this a source of satisfaction.

To decide which layout to build requires some decision as to the 'philosophy' of one’s railway, and time spent thinking over the alternatives and their relative merits will be a good investment. The design, size and character of a layout can be very different according to what aspect of railways interests the modeller. Some are interested mainly in highly detailed scenery and buildings, realistic trackside vehicles and figures, others may be interested in signalling, and will want a fully signalled layout. Others will be happy with no signals at all, however unrealistic this appears. Most modellers seem to prefer locomotives in action above all else, and the other aspects of the model take a backward place. Whatever it is, much time and effort will be saved in construction if this is decided in advance of starting.

3 Typical problems when running a model railroad

The old saying in model railroading is that the layout is never finished, and that can hold true to its word. Model railroaders can add on to the layout and some will cause problems, here is a typical list of problems and solultions:

Loops and Wyes: Whenever a model railroader wants to turn a locomotive or a train around, they have 2 options, they are a wye or a loop (tuntables are only for locomotives). Whenever the locomotive goes into the "reverse loop," the locomotive will short out and a problem will occour. If you run a Digital Command Control layout, this can be fixed with a accessory known as an auto reverser, this can be instaled on reverse loops and wyes and this (when installed) will be able to kill the short curcit on your layout and will give you plenty of enjoyment running your trains.

Expansions: Expanding a layout can be a joyus thing, sometimes anything can happen during a layout expansion and one of the major problems of a layout expansion can be one word: space. You need enough space to expand a layout, on the Trewsville Southern Railroad, space was needed to expand the layout since it had a piece of layout that came out of a baggage car. The best thing about expansions is that you better plan ahead and make sure to enjoy this great hobby.

4 Model railway manufacturers

• American Flyer
• Arnold (models)
• Athearn
• Atlas Model Railroad
• Bachmann Industries
• Berliner Bahn
• Brimalm Engineering - website
• Bing
• Broadway Limited Imports (BLI)
• Ferris (obsolete)
• Fleischmann
• Hornby Railways
• Ibertren
• Jouef
• Kato
• Klein Modellbahn
• LGB
• Life Like
• Liliput
• Lima (models)
• Lionel
• Märklin
• MTH Electric Trains
• Piko
• Rivarossi
• Roco
• Rokal
• Stewart Hobbies
• Tri-ang
• Trix Express
• Walthers

5 External links

• http://www.miniatur-wunderland.de The biggest model railway in Hamburg, Germany
• http://www.nmra.org/ The National Model Railroad Association, USA
• http://www.kleinmb.at Klein Modellbahn, Vienna, Austria (in German only)
• http://www.caorm.org/ Canadian Association of Railway Modellers, Canada
• Récréations scientifiques: Un petit chemin de fer électrique, article in French magazine La Nature , p. 32, vol. 28 (spring 1887), perhaps the earliest example of an electric rail transport toy

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