Page 15 - NMRA Roundhouse May-June 2019

Back2Basics
PART 16 – On30 Section One: The Essentials By John Levesley
Introduction
Why model On30 narrow gauge model railroads? Well narrow gauge railways have always been a popular choice, possessing on the one hand great charm but also dramatic scenic possibilities and scope for taking on a challenging but rewarding modelling activity. North America and the Caribbean region provide many examples from 42” (107cm) gauge in Canada, 36” (91.5cm) gauge in the Rockies, in the West and the Southeast to manicured 2’ (61cm) gauge lines in New England and rough and ready sugar plantations lines in Cuba, all ideal for modelling in 1/48th scale, the American O scale.
A big advantage of On30 is size. It is possible to build a home layout no bigger than an HO layout, whether on the ubiquitous 8’ x 4’ (244 x 122 cm) or even better as a shelf or modular layout. All but the most massive locomotives will fit on a 13” (33cm) turntable, meaning large steam powered 2-8-0 tender locos are shorter than many larger HO locomotives and the shorter geared or tank locos can be no more than 5 or 6” (13 or 15cm) long. Other stock is also shorter and prototypically many lines ran short trains. There are exceptions, the Colorado Narrow gauge running double headed Consolidations with 24 stock cars in trail for example, but generally speaking On30 is compact. It is for example possible to build an inglenook switching puzzle layout using the 5-3-3 rules on a board 7’ 6”x 12” (230 x 30.5cm) using one loco, two turnouts and eight freight cars.
Photo 1: Size comparison between a Bachmann HO 2-10-2 and an On30 2-8-0
For many years the modelling of these lines at this scale relied on specialist suppliers for each gauge, region and activity. What made the difference was the introduction by Bachmann of a whole series of locomotives and a representative selection of passenger and freight cars to an averaged-out gauge of 2’6” (30”) and at reasonable cost. Until Bachmann came along this was called gauge On21⁄2 but is now more commonly called On30. Despite the size of some Bachmann locos they will operate fine through Peco turnouts.
Other companies sell products for modelling On30 and other 1/48th scale narrow gauge railroads, notably the San Juan Car Company and their support for On3 modelling of
the Colorado lines. They have also developed their range to provide On30 gauge cars too.
Baseboards/Modules
When working out what size you need, remember that:
• Typically spacing between On30 track is 3 inches, 3.5 inches on curves though using smaller old timer rolling stock or logging and mineral cars may allow this to be reduced.
• Even small buildings are of some size, not just wider but higher and deeper so eight times the volume of an equivalent HO structure.
• It’s not a bad idea to design in a protective margin of about 3 inches so that the larger scale stock doesn’t fall over the edge if it derails.
Photo 2: A “small” On30 structure with an HO automobile for comparison
There are two designs that act as a basis for On30 modules in the UK, One is the FremoOn30 European design, the other the Old Track and Trestle standard promoted by the Slim Gauge Circle. Both assume the use of DCC power.
The fremoOn30 module spec proposes a track above floor height of 1.3m (about 52”) though many users in UK prefer a lower height typically 40 or 45” The single track mainline is located centrally on modules at least 30 cms wide and often 50 cms wide. There are two levels of design and presentation. Some baseboard manufacturers produce
June 2019 - ROUNDHOUSE 15