The size of a miniature, relative to what it is a replica of, is known as the scale of the figure. For a various reasons several systems are used to describe scale. Gamers primarily use X/XX (such as 1/35 or 1:35) and Xmm (such as 28mm) scales.
Some scales are given as a ratio, variously written as either a ratio (i.e., 1:35) or a fraction (1/35). The second number indicates how many units on the original equal one unit on the model.

Other scales are simply listed as a certain height, such as 25mm or 54mm. Most people usually think of this as being the height representing an average human (i.e., in 25mm scale, men are 25mm high), however some figure heights are measured to eye level, since measuring to the top of the head is impractical for figures wearing headgear. Therefore, when a manufacturer says his figures are 25mm scale, he might mean 25mm to top of the head or 25mm to eye level.

To complicate matters, recent lines of miniatures have taken to exaggerating the figure's proportions and calling it "heroic" scale, or bumping the height up a couple of millimeters. This can result in a 25mm heroic scale miniature being 28mm high. Manufacturers have been slowly making their figures a bit larger in recent years. The extra size gives more room for details, so that a large 15mm figure often looks sharper than a classic 15mm figure. GW and Reaper, two common lines of miniatures, have both moved into 28mm scale, and Rakham's Confrontation line of miniatures is even larger, about 30mm in scale.

As a final note, even figures claim to be in the same scale may differ considerably in body build, head size, and general sculpting style - even when made by the same manufacturer. Middle Earth miniature line is a prime example of this. Some manufacturers see their goal as to make scale replicas, while others concentrate on making gaming pieces which are inexpensive, durable, or easy to paint. Plastic figures may be sculpted in a thinner style than metal figures. If you are concerned whether you can mix figures from different product lines or companies you may first want to order samples from the manufacturer.

This is a short table covering the primary range of miniature scales used by gamers, particularly WarHammer players, and comparison to models and model railroad scales. The scales are based on eye-level measurements.

1/107 15mm
Pre-20th Century war gaming, also used for fantasy, science fiction, and 20th Century "skirmish-level" games

1/87 18.5mm
Model railroad HO is "half O" scale. Many railroad, scenery, and armor models available in this scale

1/80.5 20mm
Popular for skirmish-level 20th Century war gaming and science fiction

1/76 22.4mm
Same as OO scale. Plastic miniatures and kits of aircraft, vehicles, and soldiers are available

1/72 22.4mm
As above, though a slight bit larger

1/64 25mm
Popular for fantasy, historical, skirmish, science fiction, and role-playing games. Same as railroad S gauge. (American Flyer)

1/58 28mm
Heroic or large 25mm figures sometimes listed as being 28mm

1/54 30mm
Confrontation miniatures, as close as you can call for a mythical figure

1/48 33.5mm
Popular scale for plastic aircraft kits. Some display figures available in this scale

1/43 37mm
O scale in railroads. (Lionel)

1/35 50mm
Popular scale for plastic kits of armor. Occasionally used for modern gaming

1/30 54mm
Toy soldier scale, recently arrived as GW Inquisitor miniatures

To mathematically convert ratio scales into height scales, assuming that height scales measure to "eye height" while ratio scales measure to "head height", divide 1610 by the scale. For example, 1/285 figures are about (1610 / 285 = 5.6) 6mm figures. The reverse is also true: to get ratio scale, divide 1610 by the height scale. Thus, 25mm figures are equivalent to (1610 / 25 = 64.4) 1/64. The 1610 comes from using the eye height of the average man, measured in millimeters, about 1610 mm or 5' 3" to the eye. So equivalent height and ratio scales, multiplied, should always result in the same constant. So what is the constant for a manufacturer who measures height scale to top of the head, rather than to eye level? In millimeters it would be 1730 or about 5' 8".

Another problem for 40K players is the figures are not the same scale as the vehicles. Of course that can be argued as the vehicles are imaginary, so they could be any size you want.

For terrain, buy what looks good. Railroad HO bridges make excellent walkways. HO trees make good saplings or shrubs. S and O buildings and scenery works well.

Plastic armor and accessory kits in 1/35 are the best for bits and accessories (cans, barrels, etc) but most of the vehicles are too large. I have used the M113 armored personnel carrier in 1/35 for rhinos very successfully. They are much closer to the proportions of the new rhino.
Your best bet is to look at the kit whenever possible, a buy it based on size and forget the scale.

Curtesy of Railroad Brony

The gauge is the distance measured between the two rails that make up a section railway track, for example: around the world the most common gauge is 4 ft 8 1/2 ins, though other gauges exist such as 5 ft 3ins used as the standard gauge in ireland, but also in Australia & Brazil , 2ft gauge, which is the "standard" narrow gauge in the UK, 3ft gauge, which is the American equivalent to 2ft gauge, and the now defunct 7ft gauge.

it is for this reason that modellers will use specific letters or numbers to denote a particular scale/gauge combonation

T gauge (1:450):

for when space is really at a premium
T gauge is the newest, and most recent, scale/gauge combination, t's also the smallest, at 0.67818 mm (0.0267 in) to 1 ft, with a gauge of 3 mm (0.118 in). The rails themselves are a mere Millimeter high
It was introduced at the Tokyo Toy Show in 2006 by KK Eishindo of Japan, and went on sale in 2007. It is the smallest commercial model train scale in the world. Since mid-2009, Railway Shop (Hong Kong) is the exclusive licensed manufacturer. This is actually the scale that building companies use to demonstrate what a new building or city will look like.

Z scale (1:220):

dime for scale
Z scale was introduced by the Märklin company in 1972, and at 1.385 mm to 1 ft is one of the smallest commercially available model railway scales with a track gauge of 6.5 mm/​0.256 in. Z scale trains operate on 0-10 volts direct current (DC) and offer the same operating characteristics as all other two-rail, direct-current, analog model railways. Z scale locomotives can be retro-fitted with microprocessor based digital decoders for digitally controlled model railways. Model trains, track, structures, and human/animal figures are readily available in European, North American, and Japanese styles from a variety of manufacturers.

N gauge (Mixed scales):
N scale is a popular model railway scale. Depending upon the manufacturer (or country), the scale ranges from 1:148 to 1:160. In all cases, the gauge (the distance between the rails) is 9 mm or 0.354 in. The term N gauge refers to the track dimensions, but in the UK in particular N gauge refers to a 1:148 scale with 1:160 (9 mm or 0.354 in) track gauge modelling. The terms N scale and N gauge are often inaccurately used interchangeably, as scale is defined as ratio or proportion of the model, and gauge only as a distance between rails. The scale 1:148 defines the rail to rail gauge equal to 9 mm or 0.354 in exactly (at the cost of scale exactness), so when calculating the rail and/or track use 1:148 and for engines and car wheel base use 1:160.

2mm scale: Essentially the British Finescale equivalent to N scale, 2 mm scale is scaled at 2 mm to the foot (1:152) with a 9.42 mm (0.371 in) track gauge, rather than 2mm: 1 foot with 9mm track

TT scale (1:120 scale): TT scale is a niche model railroading scale, whose name stands for table top.

Its 1:120 scale (from a common engineering scale where one inch equals ten feet) and 12 mm (0.472 in) gauge sizes it almost halfway between HO scale (1:87) and N scale (1:160). Its original purpose, like the name suggests, was to make a train small enough to be able to assemble and operate it on a tabletop.

TT retains a comparatively small niche in the United States and in the United Kingdom, but growing popularity in the former East Germany; it is the second most popular scale in Eastern Europe and Russia. Adherents to TT maintain it is the smallest practical scale, especially for those who like to build models from scratch.

3mm scale (1:101): also known as 3 mm finescale, is a model railway scale of 3 mm: 1ft used for British prototypes. Introduced as British TT gauge, it sits approximately halfway between British N gauge and OO gauge, but is not as popular as either and there is no longer any mass manufacturer ready-to-run support. When TT gauge model railways were developed for British prototypes, in order to fit the small British prototypes, the scale was enlarged but without altering the 12mm gauge. The result, British TT gauge, is too narrow. This led to the development of 14.2 mm (0.559 in) gauge 3mm finescale. Thus two finescale standards were developed. By far the more common of these is 14.2 mm gauge track, which is accurate. Some modellers choose to use slightly narrower 13.5 mm track due to the necessary oversize motion of outside-cylindered steam locomotives.

HO (1:87): HO or H0 is the most popular scale of model railway in the world.

According to the National Model Railroad Association (NMRA) standard S-1.2 predominantly used in North America, in HO scale, 3.5 mm (0.1378 in) represents 1 real foot (304.8 mm); this ratio works out to 1:87.0857142, usually rounded to 1:87.1.[3] According to the MOROP standard NEM 010 predominantly used in Europe, the scale is exactly 1:87.[4] In HO, rails are spaced 16.5 mm (0.64961 in) apart which models the standard railroad gauge of 1,435 mm (4 ft 8 1⁄2 in).

HOn2 scale: American HO scale narrow gauge models using 7 mm (0.276 in) track to represent American prototypes, especially those in Maine, with a 2' track gauge. No known commercial activity.

HOe scale: European HO scale narrow gauge models using 9 mm (0.354 in) (the same as N scale) track to represent prototypes with gauge between 650 and 850 mm (25.6 and 33.5 in), particularly 750 mm (2 ft 5 1⁄2 in) and 760 mm (2 ft 5 15⁄16 in) gauge.

HOf scale: European H0 Scale narrow gauge models using 6.5 mm (0.256 in) (the same as Z scale) track to represent prototypes with gauge between 500 and 650 mm (19.7 and 25.6 in). The "f" represents feldbahn, or forest railway, and these narrower track gauges were frequently used for industrial operations all across Europe. Some of these lines survived until 2000 and even later, particularly in Eastern Europe, where they remained economically viable later than in the west. In 2010 the German company Busch announced a feldbahn line, and followed it with a grubenbahn (mine railway) line in 2012. An innovative track system uses magnets to increase adhesion for tracking and increased engine performance.

HOn3½ scale: H0 scale using 12 mm (0.472 in) gauge track to represent 3 ft 6 in (1,067 mm) used as "standard" gauge in many African countries, New Zealand, Queensland, Japan, etc. European H0m ('metre gauge') models represent prototype gauges ranging between 850 and 1,250 mm (33.5 and 49.2 in).

Proto:87: 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.

OO scale (1:76): This scale is today the most popular modelling scale in the UK (and the scale used by yours truly ), although it once had some following in the US (on 19 mm/​0.748 in gauge track) before WW2. 00 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. 00 uses the same track as HO (16.5 mm/​0.65 in 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 0 Gauge Association to promote this scale.

EM gauge: EM gauge was an earlier attempt in the 1950s to improve the inaccuracies of OO gauge, with wider, more accurate track at 18 mm (0.709 in) between the rails, but still narrower than the correct gauge. The gauge was later widened to 18.2 mm (0.717 in). The UK-based EM Gauge Society exists to supports modellers of these standards.

P4: P4 was created in the 1960s as the most accurate possible standards for modelling in 4 mm scale. Supported by the UK based Scalefour Society. P4 stands for "Prototypical 4mm" and uses 18.83 mm gauge.

0012: Narrow gauge modelling of 3 ft (914 mm) prototypes on 12mm gauge (the same as TT scale) track.

OO9: Narrow gauge modelling of approximately 2 ft (610 mm) or 2 ft 6 in (762 mm) prototypes on 9mm gauge (the same as N scale) track. It supported by a dedicated society and has a flourishing supply of kits and parts from many small UK-based suppliers.

006.5: a very uncommon 4mm scale gauge used to represent 15 inch gauge, ride-on miniature railways such as the Ravenglass and Eskdale Railway, Romney, Hythe and Dymchurch Railway, and locally to myself, the Cleethorpes Coast Light Railway, I have only seen this modeled once, by a guy from japan who was trying to recreate the Arlesdale railway from the Railway Series, so it technically isn't an official gauge/scale combination.

Kit scale (1:72): as the name suggests, this scale is most commonly used scale for model kit companies such as Airfix and Revell. it is generally acceptable to use it in conjunction with OO scale

S scale (1:64): 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 used this gauge, 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. In the United States, S scale has a small but growing following in the modelling of standard gauge railroads, especially those of the 1940s and 1950s era, a focus that is supported by S Helper Service[6] and American Models,[7] among others. This scale is also popular in North America to depict 3 ft (914 mm) narrow gauge prototypes (using dedicated 14.28 mm (0.562 in) gauge track and known as "Sn3"), and elsewhere to depict the 3 ft 6 in (1,067 mm) narrow gauge railways (using H0 scale 16.5 mm/​0.65 in gauge track and known as "Sn3½") of South Africa, Australia and New Zealand. the only offerings in this scale here in the UK is Hot wheels cars.

O scale (1:43.5 (Great Britain and France),
1:45 (Germany, Japan, Russia and Czech),
1:48 (US)): Name originally was '0' (zero), '1' through '6' were already in use for larger scales. In the US, this is frequently considered a 'toy train' scale rather than for scale modellers. However, though toy trains use this gauge, they are often nowhere near scale. Scale modellers have begun to use this gauge for their scale models, resulting in a two separate groups of modellers within this "scale": "hi-railers", those who run toy train equipment on oversized track and scale modellers, who run scale equipment on scale track. A limited few have been able to combine both. Nowadays, even high-railers have the option of extremely precise scale models and track. Lionel, LLC, MTH Electric Trains, Atlas O, Basset Lowke (UK) and Bachmann Europe PLC are major manufacturers of this scale. While in Russia and former Soviet countries is used gauge of 1,520 mm (4 ft 11 27⁄32 in), but for the models, the norms of standards NEM. Therefore, the gauge for the models is 32 mm, rather than about 34. In this model, the rolling stock are made in scale 1:45.

ScaleSeven: Exact scale version of British O gauge supported by a dedicated UK based society. The ScaleSeven Group defined more scale measures more strictly (e.g., the model gauge of 33 mm is fixed). Apart from standard gauge, it also defined Irish and Brunel gauges to this scale.

Proto:48: These are to the same scale as US O gauge but are accurate scale models in all dimensions including track and wheels.

OJ: O-scale models of 3 ft 6 narrow gauge prototypes running on 24.0mm gauge track. Virtually unknown outside Japan and Taiwan.

On2: O-scale models of 2 ft narrow gauge prototypes running on 1/2in (12.7mm) gauge track.

On30: Narrow gauge O-scale models running on HO gauge track. This scale was initially created by American "kit-bashing" modelers desiring large scale narrow gauge at low cost, at a time when the existing On3 market was dominated by expensive brass models. They put small O-scale superstructures on HO-scale mechanisms and trucks, but when the large company Bachmann issued train sets – originally intended to run around Christmas trees – On30 really took off.

O16.5: British narrow gauge running on HO gauge track. Prototypes of many diverse gauges are depicted in this scale, as well as fictitious lines. Even two foot lines - particularly slate - are represented, although serious modelers with this interest generally prefer O-14.

0e: Continental European (mostly German and Austrian) narrow gauge running on HO gauge track. Fleischmann produced the Magic Train line, intended for the toy market, but also adopted by serious modelers, particularly when supplemented with protypical details - or "bashed" to be closer to the prototype. A number of smaller manufacturers produce a wide range of elements, including the high-end Henke, offering exquisitely accurate models for a handsome price. 0e has many active participants in Germany, with frequent Fremo modular meets on weekends.

O14: Accurate modelling of 2 ft narrow gauge in 7mm:ft/1:43.5 scale supported by an informal web based society.

L gauge (1:38-ish): Unofficial designation of toy trains built from LEGO. Equipment can be built to differing widths in relation to the track gauge, and are becoming increasingly popular among persons who grew up with the building toy system. With Technic axles and custom train wheels, it is possible to build Lego trains wider than standard 6-stud wide to fit into any gauge like G or O gauge.

Gauge 1 (1:32): This large scale, once rarely seen indoors in modern use but frequently used for modelling standard gauge trains as garden railways, is making a come-back. The Japanese firm of Aster Hobby offers ready-to-run gas-fired live steam models. Accucraft Trains also offer finely crafted live steam models in this scale. 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 electrically powered and live steam locomotives and rolling stock in ready to run, parts and kit form. Some manufacturers offer so-called Gauge 1 items in 1:30.48 scale (10 mm = 1 foot) that also run on 45 mm (1.772 in) gauge track. Gauge 1 also has its own international association.

Gauge 2 (1:29): The dominant scale used in the United States for models of "standard gauge" trains running on 45 mm (1.772 in) track, even though 1:32 is more prototypically correct. 1:29 represents standard gauge using 2 in (50.8 mm) gauge track, the original gauge 2. This fell into disuse as gauge 1 at 1.75 inch was very close. Some manufacturers kept the scale for the models but running them on slightly narrow gauge track.

G scale (various): (Originally from the German groß (Grosse) (meaning "big"), now also G as in Garden) G is generally used for garden railways of narrow gauge prototypes, and uses the same track gauge as 1 gauge, below. The scale ranges approximately from 1/19 to 1/29, according to the size and gauge of the prototype.

16 mm scale(1:19): This scale was first developed in the UK in the 1950s to depict 2 ft (610 mm) narrow gauge prototypes using 32 mm (1.26 in) 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 ft (610 mm) narrow gauge prototypes have also adopted this scale for use alongside the near-compatible Fn3 (15 mm or 1: 20.32) scale on 45 mm (1.772 in) 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.

Gauge 3 "King Gauge" (1:22): One of the original model railroad scales standardized in 1909, a minority interest, which is undergoing a revival in the UK and in Germany (where it is known as Spur II). 64 mm (2 1⁄2 in) gauge 3 track is commercially available, as are a growing number of locomotive and rolling stock kits. The European standard of 1:22.5 scale trains on 45 mm (1.772 in) track is called IIm scale, as per European narrow gauge naming conventions or G scale, its popular name.

there are other scale/gauge combinations in existence, though this is usually in the realm of scratch building, one example would be modelers who represent Brunel gauge, or 7ft

I recall coming across an O scale layout which featured dual gauge track of 4ft 8 1/2 and 7ft gauges, all the track had been scratch-built, as had the 7ft gauge rolling stock, the Standard gauge rolling stock may have been kit built, but it wore than likely would have also been scratch built

In a time where some people can be strapped for cash, printable kits are a cost effective way to add buildings to your layout, and make for a fun afternoon, the beauty of the concept of downloadable kits is even when you have to pay you can print them as many times as you want after the initial payment.
for these websites you will need:

Adobe Reader: to access the files and print them off

Winzip or 7zip: some of the kits are in compressed folder, so a zip-file reader is recommended to unzip them

Wordsworth Model Railways

smartmodels.co.uk

modelrailwayscenery.com

http://www.scalescenes.com/

Need a fictional town name for your layout or diorama? Maybe even names for your fleets of boats or industrial locomotives? then go no furthar than http://www.namegenerator.biz/

examples of place names include:
Northbarrow
Maplebank
Foxland
Clearmoor
Fallgriffin
Greenbarrow
Snowwick
Bluehill
Starrybank
Aldshore
Lorview
Beechden
Ironbridge
Whitegriffin
Newedge
Foxbridge

Examples of ship names (they can be adapted to model locomotives) include:
Blue Magoo
Dragons Flight
Out There
Bigger
Motion Granted
Eagle III
Charisma
Lure Me
Brilliant
Full Monty
Oasis
Meant To Be
Sandy Endeavor
Miss Behavin'
Chamed Life
Dream Hunter
Diamonds On The Water
Barely Twisted
Impact II

Here's another name generator:
http://fantasynamegenerators.com/

there's also a website, designed for roleplaying, that gives you a selection of town names from a specific area, for instance Scotland or England
http://abarothsworld.com/roleplay.htm

Tip: If you're setting your layout or diorama in Wales or near some selected communities in Argentina, then you can create a really authentic sounding fictional town name by translating one of the generated names from English into Welsh, for example

Bluehill - blue hill - bryn glas - Brynglas

the same can be done for boat or locomotive names

Swordfish - cleddbysgodyn

1. Precision Screwdrivers:

if you have to buy any item first, it has to be a nice set of screwdrivers, they aren't that expensive, a reasonably sized pack is only about £10, and they're a key tool for maintenance of locomotives.

2. Track rubber:

This is the second piece of equipment that you absolutely must have, they are usually sold as 5 cm blocks that are made of rubber mixed with filings or something similar. And are used mainly for getting dirt off of the track. Ask anyone who's a part of the model railway hobby and they will tell you that no other forms of cleaning can compete with good, old fashioned elbow-grease.

3. Fiberglass burnishing pencil:

this is to rolling stock wheels what the track rubber is for track. usually sold for around £5. They can also be used for burnishing the plastic of a model so it's ready for painting
A useful tip to bare in mind; wear gloves! Seriously, they are made of fiberglass, and the fibers are attracted to you skin like no tomorrow, and they itch like a fucker

these next few are particularly useful if you use kadee/knuckle couplers or live in the states

4. Coupler height gauge:

Nothing is more frustrating than having a train come apart on you and rolling down a 2% grade, the caboose derailing, and the whole mess taking a trip to the floor because one coupler was higher than the other. (15 cars of a 40 car coal train, using "live loads" of crushed anthracite. Layout owner had a shop-vac on hand for such an occasion. It is only used when something like this happens.)

5. Needlenose pliers:

good for bending the trip pins on knuckle couplers up so they don't pick the switch and derail

6. NMRA standards gauge:

Helpful for checking the track gauge and clearance of cars.

7. Loading gauge:

a bit like the NMRA standards gauge, this is used for setting the clearance whilst you're building the layout, especially if it's based on British or European practice, it usually comes in he form of an A3 sheet of paper (i've got a slightly different version that has all the measurements in different scales on a separate sheet)

8. Back-To-Back tool:

this handy little tool can help to ensure your rolling stock stays on the rails by setting the inside faces of the wheels to the correct distance part, in the case of OO and HO this is 14.5 mm apart.

9. Track gauge:

this is used to ensure the track is the correct distance apart, Peco are one company that makes this.

10. Tracksettas:

if you model with flexi-track, the tracksettas are your best friend, they can be used to get professional looking curves on your corners, If you use kit built locomotives in OO or HO scale then i'd strongly advise against using curves any sharper than 36 inches/3 feet radius, something i personally like to call "3 foot standard" as it's an unofficial standard adopted by finescale modellers, where none of the curves are sharper than 3 foot.

channels that are great for their all-round content, whether it's reviews, how-tos, or just hints and tips

Everard Junction: 1980/90s british oo scale, videos include how-tos, weathering domos, scenery demos, and a vlog charting the progress of his own layout as well as the occasional review

Intercity82: an eclectic mix of oo scale models with the occasional ho scale model, does fantastic reviews, just starting to branch out into reviews and how-tos

Monster Railroad: HO scale, does excellent how-tos and is very talented at weathering

Erics Trains American o gauge 3-rail, does fantastic, in-depth reviews, also does a blog for his layout

04clemea: OO scale, has a fantastic layout of kings Cross in london, as well as videos of real trains, great for inspiration

Making waves:

Link
Caters for all scales, and you get a selection of distances, if you want to get any particular speed then you'll have to rely on guess work and use of decimal places

here's a few examples, using OO scale as an example with the time taken to cover 3 foot in seconds:

10 MPH (Yard speed): 15.54
25 MPH (maximum speed for unfitted freight trains or light-railways, also applies to preserved lines): 6.217
60 MPH (Maximum speed for fitted/modern freight trains, steam era passenger trains): 2.591
70 MPH (average speed for steam era express trains): 2.2209
100 MPH (Flying Scotsman's record): 1.5545
125 MPH (UK rail speed limit): 1.2436
125.88 MPH (World steam speed record): 1.2349

Baseboards

I never would have thought about using a 2 inch foam base on top of the plywood, certainly makes adding sub-track lever features such as a river or stream really simple, also adds some structural rigidity whilst keeping it lightweight