Layout complexity may vary from a simple circle or oval track to realistic reproductions of real places modeled to scale. To enhance their knowledge and experiences, these serious hobbyists gather at model railroad clubs where they talk the talk and walk the walk of model railroad engineers. The large scale (garden variety) models are usually hand-built and powered by live steam, or diesel-hydraulic, and the engines are often powerful enough to haul dozens of human passengers.

These hobbyists, called “railway modelers” or “model railroaders”, may maintain models large enough to ride on (Garden Railroading). Modelers may collect model trains, building a landscape for the trains to pass through, or operate their own railroad in miniature.

Scales and assesses

Scale is the model’s measurement as a proportion to the original, while gauge is the measurement between the rails. The key is to stick to your choice once you have decided on a scale, and not mix scales in a single layout.

Recently, another scale that was introduced that is also commercially available, called T Gauge, it is 3 mm (0.118 in) gauge track and is a scale of 1:450, basically half the size of Z scale. The most popular scales are: G gauge, Gauge 1, O gauge, S scale, HO gauge (in Britain, the similar OO), TT scale, and N scale (1:160 in the United States, but 1:144 in the UK). Popular narrow-gauge scales include Sn3, HOn3 Scale and Nn3, which are the same in scale as S, HO and N except with a narrower spacing between the tracks (in these examples, a scale 3 ft (914 mm) instead of the 4 ft 8 1⁄2 in (1,435 mm) standard gauge).

G scale (Garden, 1:24 scale) is most popular for backyard modeling. It is easier to fit a G scale model into a garden and keep scenery proportional to the trains. Lionel trains in O scale (1:48 scale) are popular toys.

Connectors and couplers

In H0, the Americans standardized on horn-hook or X2F couplers, though these have actually mostly paved the way to working knuckle couplers which are a close approximation to the “automated” couplers utilized on the model there and somewhere else. In H0, the European manufacturers have standardized, but on a coupler mount, not a coupler: many varieties of coupler can be plugged in (and out) of the NEM coupler box. None of the popular couplers has any similarity to the model three-link chains usually utilized on the continent.

Other scales have comparable varieties of non-compatible couplers offered.

Bachmann and more recently Hornby have begun to offer models fitted with NEM coupler pockets. This theoretically enables modelers of British railways to substitute any other NEM362 coupler, though many Bachmann models place the coupler pocket at the wrong height.

In addition to various scales, there are likewise various kinds of couplers for linking automobiles, which are not suitable with each other.

Source of power

As accuracy became important some systems adopted two-rail power in which the wheels were isolated and the rails carried the negative and positive supply or two sides of the AC supply.

These hobbyists, called “railway modelers” or “model railroaders”, may maintain models large enough to ride on (Garden Railroading). To enhance their knowledge and experiences, these serious hobbyists gather at model railroad clubs where they talk the talk and walk the walk of model railroad engineers. It is easier to fit a G scale model into a garden and keep scenery proportional to the trains. The electric-outline model would be supplied by the other model and the overhead wire (usually steam-outline) would be supplied by one of the running rails. Batterypower is used by many garden railway and larger scale systems because of the difficulty in obtaining reliable power supply through the rails outdoors and because the high power consumption and thus current draw of large scale garden models is more easily and safely met with rechargeable batteries.

Other systems such as Mrklin instead used fine metal studs to replace the central rail, allowing existing three-rail models to use more realistic track.

Many early designs for the toy market were powered by clockwork and managed by levers on the engine. This made control crude the models were robust and large enough that grabbing the controls was practical. Different makers presented slowing and stopping tracks that might activate levers on the engine and enable station stops.

Live steam

Internal combustion

Two-rail

The industry standard command system is Digital Command Control (DCC). The advantages to DCC are that track voltage is constant (usually in the range of 20 volts AC) and the command throttle sends a signal to small circuit cards, or decoders, hidden inside the piece of equipment which control several functions of an individual locomotive, including speed, direction of travel, lights, smoke and various sound effects. This allows more realistic operation in that the modeler can operate independently several locomotives on the same stretch of track.

Control

Clockwork

Batterypower is used by many garden railway and larger scale systems because of the difficulty in obtaining reliable power supply through the rails outdoors and because the high power consumption and thus current draw of large scale garden models is more easily and safely met with rechargeable batteries. Most large scale battery powered models use radio control.

Model railway engines are generally operated by low voltage direct current (DC) electricity supplied via the tracks, but there are exceptions, such as Mrklin and Lionel Corporation, which use alternating current (AC). Other locomotives, particularly large models, used steam.

Engines powered by Live steam are often built in large, outdoor gauges, and are available in Gauge 1, G scale, 16 mm scale and can be found in 0 and H0. Hornby Railways produce live steam locomotives in 00, based on designs first arrived at by an amateur modeler. Other modelers have built live steam models in H0/00, 009 and N.

Overhead line

Electrical power

Stud contact

Electricity permits control by dividing the layout into isolated blocks, where trains can be slowed or stopped by cutting or lowering power to a block. Dividing a layout into blocks permits operators to run more than one train with less risk of a fast train catching and hitting a slow train.

As trains began to be powered by rectifiers and transformers more sophisticated throttles appeared, and soon trains powered by AC contained mechanisms hydraulic quick coupler excavator  to change direction or go into neutral gear when the operator cycled the power. Trains powered by DC can change direction by reversing polarity.

Early electrical models used a three-rail system with the wheels resting on a metal track with metal sleepers that conducted power and a middle rail which provided power to a skid under the locomotive. In addition the notion of accurate models had yet to evolve and toy trains and track were crude tinplate.

Where the model is of an electric locomotive, it may be supplied by overhead lines, like the full-size locomotive. The electric-outline model would be supplied by the other model and the overhead wire (usually steam-outline) would be supplied by one of the running rails.

Battery

Occasionally gasoline-electric models, patterned after real diesel-electric locomotives, come up among hobbyists and companies like Pilgrim Locomotive Works have sold such locomotives. Large-scale petrol-mechanical and petrol-hydraulic models are available but unusual and pricier than the electrically powered versions.

Three-rail