Model Railway Scales & Gauges

Model Railway Scales

Model railways have many different scales & to the beginner can be quite confusing as to what the likes of N, OO, EM, HO all means. We’ll take a look at what scales there are & a more in-depth look at some of the more popular scales. The scales range from the very very tiny  T gauge right up to the bigger scales of G. So there is a scale to suit most folks available spaces around the home & outdoors in the garden. In the image below shows a size comparison between scales Z right up to G1.

So as can be seen in the image there is quite a size difference between  Z & G scale (T gauge isn’t shown but is smaller than Z gauge). A list of gauges & scales are shown in the table below:

Popular gauges

The most three popular scales/ gauges in the UK are:

• OO/4mm:1ft
• O gauge/7mm:ft
• N gauge/2mm:ft

N Gauge

We’ll start off with N gauge. N gauge is becoming more increasing in popularity over recent years. With the increase of detail & quality, improved motors & mechanical upgrades, lighting, DCC & DCC sound have helped elevate N gauge’s popularity. Compared to a couple of decades back, N gauge is now in a different league altogether. A wide & good selection of quality N gauge track, with an ever growing range of accessories & scenic kits, it’s never been a better time to start modelling in N gauge. The likes of Rapido Trains, Revolution Trains, Dapol among others are pushing the boundaries in both terms of detail & quality of N gauge.

N gauge is half the size of OO thus takes up less space which means you can pack in much much more into the same space or area you have available to you. Full-length trains can be run where you may be struggling with space to run the same length train in OO scale. More realistic gentler radius curves & bigger stations with less compromise than OO scale. Junctions & curves appear more realistic in N gauge & the extra space means more striking impressive landscape modelling can be created. Some great examples of layouts built in N gauge have been: Crianlarich in Scotland, Parts of the Settle Carlisle line, East & West Coast Mainline & the approaches to Kings Cross, just to name a few!

N gauge can be a disadvantage due to its size for handling so if you struggle with eyesight problems, or have young children the models may not be as resilient as their OO scale counterparts. In some cases working in this scale may mean working with a magnifying glass or similar might be a frustrating factor.

• Pros

• More scope for scenic modelling large areas
• More realistic train lengths
• More realistic curves & junctions
• Improved & growing range of N gauge items
• Improved & better quality locos & rolling stock
• DCC sound

• Cons

• Unsuitable for hard of sight
• Unsuitable for small children
• Fiddly parts
• Not as many accessories offered as OO scale (but is getting better)
• Large couplings

O Gauge

O Gauge 7mm:ft is making something of a comeback & is increasing more in popularity. The range of ever growing ready to run items at reasonable prices is attracting many to this scale. O gauge models run on 32mm gauge track. The likes of Heljan, Dapol, Skytrek through their locos, rolling stock & scenic accessories (including our own growing O gauge of kits here SMS HQ), steadily bringing more new items to market. A steady stream of steam & diesel classes such as the 08, 20, 26, 31, 33, 37, 40, 52, 55, & much more to come including matching coaching stock & wagons ensures a good wide selection is available for everyone.

O gauge was originally the preserve of kit building with many excellent kits. But with the increase in availability & popularity of the ready run models, mean many can now take to this scale who may not be confident in their kit building skills. The range of items for O gauge isn’t as comprehensive as OO scale but it is steadily growing. With the size of O models, it allows models to be much more detailed than it’s smaller OO counterpart, with many truly stunning miniature replicas of the real thing. O gauge offers more scope with more detail interiors, finely molded bodies & underframe details.

The downside is the price for some modellers with some ready to run locos costing around the £600 mark. With the limited edition numbers produced means, some models sell out very quickly indeed. Another factor is the space needed for an O gauge layout. Though small loco shed based shunting layouts in O gauge are very popular.

• Pros

• Great for larger spaces such as Garden Railways
• Superb & more realistic details
• Improved & growing range of O gauge items
• Growing range of ready to run models
• DCC sound in O allows much bigger impressive speakers to be fitted

• Cons

• Higher price
• Limited off the shelf track types
• More space needed for a layout
• Sharper curves needed on small layouts

OO Gauge

By far this is the most popular scale/gauge in the UK. OO gauge/4mm:1ft has an impressive & massive growing selection in both terms of locos, rolling stock kits & accessories. The quality of the models in this scale is improving all the time, with an ever growing high quality of selection of products hitting the market. The likes of Rapido Trains, Revolution Trains, Suttons Loco Works, Accurascale, Calvex, Hattons, Kernow & Dapol all raising the bar massively, meaning the two bigger well know names are now following suit.

The choice of scenic items & accessories range is tremendous, ranging from ready to plant items to high-quality kits, means most things you can think of are covered or soon will be.

OO scale is specific namely to the UK. It uses the 3.5mm:1ft HO gauge scale track with a gauge of 16.5mm. The correct gauge for4mm:1ft scale is 18.83mm so OO is a form of compromise, this isn’t helped by the 3.5mm:1ft scale sleepers. Though there is several spin-off scales that offer the correct fine scale track, these being EM & P4 scale which use OO scale locos & rolling stock which have to be modified to the wider EM & P4 scale. Though for many folks, they can live with the compromise in the scale of the track.

OO scale track comes in various rail heights such as code 100 (the most popular – this is the one that comes with the likes of Hornby & Bachmann Train sets) & code 75. Track sleepers are available as wooden type, concrete type & also metal sleeper type. Track systems such as Peco offer a large range of track & point work which some being compatible with Hornby/settrack type track work.

Many OO scale layouts can be restricted due to space available such as room available in a spare room, loft, shed, garage etc. A basic continuous run type layout can be fitted on a 6′ by 4′ baseboard. Though longer layouts can be incorporated on to a L or U shaped layout. End to end type layouts are also popular, these take up less room and are a bit of a compromise but can incorporate a lot of scenic detail.

If you have a lot of space available, then full-length stations can be incorporated. A full-length station platform will scale out at over 10ft in OO scale. DCC has & is developing at quite a pace, it’s brought the likes of DCC sound to market has helped spur on the OO scale market in recent years. DCC technology offering more realistic operation to OO gauge is adding more value to play & operating a layout in OO scale.

• Pros

• Great for children & new beginners to the hobby
• Superb & more realistic details
• Improved & growing range of OO gauge scenics items
• Growing range of ready to run models
• DCC sound
• Excellent range of track work

• Cons

• Space limitations
• Limited length of trains
• Compromised incorrect OO scale track
• Sharper curves needed on small layouts
• Price increase on some ready to run models