Tiny Trainset: a free browser train set, and a plain guide to model railways

Gauge and scale are not the same thing

The two words get used interchangeably and they mean different things. Scale is the ratio between the model and the real thing. Gauge is the distance between the inside running edges of the two rails. You can have several scales sharing one gauge, and one scale running on several gauges, and British modelling contains examples of both.

Britain's standard gauge railways are built to 4 ft 8½ in, or 1,435 mm. That figure is the starting point for every calculation below.

Two rows in that table share a gauge, and the reason is the most quoted oddity in British modelling. At 1:76.2, standard gauge should measure 18.83 mm between the rails. OO runs on 16.5 mm, so the track is around 2.3 mm too narrow for the bodies riding on it. That happened because British locomotives and carriages are physically smaller than their continental and American equivalents, and the electric motors available when the scale was settled in the 1930s would not fit inside a body built at 1:87. The bodies were enlarged to 4 mm to the foot, the HO track was kept, and Britain has lived with the compromise ever since.

Modellers who find that hard to ignore use the finescale standards instead: EM gauge widens the track to 18.2 mm, and P4 goes to the full 18.83 mm with matching wheel and track tolerances. Both mean building or converting rolling stock rather than buying it off the shelf, which is exactly the trade being made.

The practical consequence of choosing a scale is floor area. A double-track oval with a couple of sidings sits comfortably on a board around 6 ft by 4 ft in OO. The same plan in N fits on roughly 4 ft by 2 ft 6 in. In O it wants a garage.

Curves, gradients and clearance decide what you can run

Sectional track is sold by curve radius, and in OO the standard British set-track radii are 371 mm (first), 438 mm (second), 505 mm (third) and 572 mm (fourth). Those numbers matter more than almost any other decision on a layout.

Short four-wheeled wagons and small tank engines will happily go round first radius. Bogie coaches and large express locomotives often will not, and even when they do, the overhang looks wrong and the buffers of adjacent vehicles can lock and lift stock off the rails. As a working rule: first radius for shunting and short trains only, second radius as the practical minimum for anything with bogies, third or fourth for main line stock, and flexible track set to a wider radius still if you want it to look convincing. Flexible track costs you the convenience of clip-together geometry and repays it in appearance, because you choose the radius rather than accepting one of four.

Curves also affect spacing. On a curve the middle of a long vehicle swings towards the inside of the arc while its ends swing outwards, so two long vehicles passing on adjacent curved tracks need more space between the track centres than they do on the straight. Set-track systems solve this by fixing the spacing for you, which in Peco's OO Setrack range is 67 mm. If you are laying flexible track by hand, check the clearance with your longest two vehicles before the glue sets rather than after.

Gradients are the other constraint people underestimate. Around 1 in 40 is a sensible maximum for a model that has to pull a train up it, and gentler is better. For comparison, the Lickey Incline in Worcestershire is about 1 in 37.7 and is famous precisely because a main line that steep is unusual. Whatever gradient you choose, ease the transition at the top and bottom over a foot or so: an abrupt change in vertical angle will lift couplings apart and ground the middle of long vehicles.

Track plans that fit in a real room

Most layouts are one of two shapes. A continuous run, usually an oval or a figure of eight, lets a train run unattended, which is what most people at home actually want. An end-to-end layout runs from one terminus to another and mirrors how real railways work, but it needs somewhere to turn trains round or a way to represent the rest of the network.

That second job is done by a fiddle yard: an off-scene set of storage roads where trains are rearranged by hand between appearances. Variants include a sector plate that pivots, a traverser that slides sideways, and cassettes that lift a whole train off the layout. None of it is meant to be seen, and all of it is what makes a small scenic section busy.

Two long-established shunting puzzles are worth knowing because they pack real operation into almost no space:

• Inglenook Sidings uses three sidings holding five, three and three wagons, plus a headshunt that takes the locomotive and three wagons. Eight wagons are placed at random and the task is to assemble a specified train of five in order. It fits along a shelf a few feet long and it is genuinely difficult.
• Timesaver, devised by the American modeller John Allen, is a similar idea built around tight siding capacities and a stopwatch. It is a puzzle first and a railway second, which is the point.

Two pieces of advice apply to any plan. Draw it full size before you buy anything, because track geometry rarely closes up the way it does in your head. And do not build anything you cannot reach: if a section of track sits more than about two and a half feet from an edge you can get to, at some point it will derail there and you will have to lean across the scenery to fix it.

DC and DCC

DC, the traditional analogue system, works by varying the voltage on the rails. Turning the knob raises the voltage and the train speeds up, and reversing the polarity reverses the train. Because the control is applied to the track rather than the locomotive, every locomotive on an electrically connected section responds together, so running two trains independently means dividing the layout into isolated sections with switches.

DCC, or Digital Command Control, puts a constant signal on the track that carries both power and digital instructions. Each locomotive has a decoder with its own address and obeys only the packets addressed to it, so several trains can be driven independently on the same piece of track, with directional lighting, gradual acceleration and sound if the decoder supports it. The standards are published by the NMRA, which is why decoders and controllers from different makers generally work together.

DCC costs more to get into and adds a decoder to the price of every locomotive. It earns that back if you want independent control, prototypical shunting or sound. For a single train running round an oval, DC remains completely adequate and always will be.

Heritage railways as reference material

Britain has over 150 heritage and preserved railways, and they are the most useful reference source a modeller has, because almost everything on them can be photographed and measured at close range: station buildings, platform edges, signals, fencing, lamp posts, colour schemes, the exact grubbiness of a working locomotive.

A few are historically significant in their own right. The Talyllyn Railway in Gwynedd was the first railway in the world to be taken over and run by volunteers, in 1951. The Bluebell Railway in Sussex, reopened in 1960, was the first preserved standard gauge line in the world to run a public passenger service. The Ffestiniog Railway, incorporated by Act of Parliament in 1832 to carry slate down to Porthmadog, is among the oldest surviving railway companies anywhere.

Compact lines are often the most useful to model, because a real station on a five mile railway can be reproduced without editing it down. There is a longer piece on ten of Britain's heritage railways elsewhere on the site, and the guide covers getting started in more detail.

About the simulator

Tiny Trainset is a small 3D wooden train set that runs entirely in the browser. It is deliberately simple: there is no scoring, no timer, nothing to complete and no account to create. It is closer to a digital fidget toy than to a game, and it borrows the look of a wooden toy train rather than the proportions of any real locomotive.

What you can do with it

• Control the train: adjust speed and direction, and turn smooth acceleration on or off
• Choose a layout: switch between the oval, figure of eight and double loop presets
• Build your own: place straight and curved pieces on the grid, rotate them, and clear the lot to start again
• Change the scene: tabletop, grass or studio, at day, dusk or night
• Change the palette: classic wood, bright, soft pastel or natural tones
• Move the camera: orbit the scene, follow the train, or watch from the side or above
• Adjust the rendering: shadows on or off, and zoom
• Come back later: your settings and any track you build are saved in your browser