The Portable Railway Collection

In an early photographic essay I painted a picture of the various train-related activities in which the kids and I were engaging. This is a more complete archive of our own layouts, electronics, layout theory, and general information.

These layouts are created in Marklin's Z-scale (that's 1.4mm to the foot, in British-speak), the smallest commercial scale available. Z-scale is 220:1 (compared to N at 160:1, through G at 22.5:1). It is this scale, and the standard minimum turn radius of 150mm (6"), that allows for the extreme portability of some of the designs.

The Alpine - The first of the series.
The Polar Express - Modelled on the children's book, now a movie.
The Zoo Table - A piece of furniture for the enthusiast. (Not for sale.)
The Suitcase - A prop for a short film, and a damn small design.
Merinda's Zootcase Layout - A pizza-style layout of a Zoo by Merinda, age 9.
Zannulus - A Z-scale layout in annular form built as a coffee table from the Jetson's era.

These layouts are in N-scale (that is 2mm to the foot, Brits). N-scale has a nominal minimum turn radius of 9" (228mm), implying a minimal circle within 20" (500mm). I have some Trix track with a turn radius of 7.75", implying a circle that fits in a 17" (430mm) diameter space. Some rolling stock experiences difficulty negotiating the minimum turn radus, and it has difficulty with the tight trix turn. My first few layouts do not use less than 9" turn radius, in the interest of accomodating rolling stock.

Tomix make a spectacular range of track and trains, but these are not widely promoted outside of Japan, and catalogs are not available except in Japanese. Notably, Tomix make N-scale curves with 103mm (4") and 140mm (5.5") radii, and points in the 140mm system. As of 2006 I was able to find only two sites in English that sell Tomix track, one in Germany ( and one in Australia (, but these are ephemeral.

Santa Rosa N - The first one made at Vallejo St, based on Santa Rosa. (Sold.)
The Scenic N - Based on the "Woodlands Scenic" topology, with additions. (Sold.)
Edwin's 4th Birthday N - For Edwin to use by himself, a lightweight 2x4 with tunnels, branch line, and siding. (Not for sale.)
The Pizza Hill - What can fit in the space of just one circle?
The Journey N - Finished at last. A layout of unusual dimensions.
The Sea-Quarry N - An automated end-to-end layout in N-scale, and my first with below-recommended radius of curvature.
SpiritiNg Away - A brief folly of a layout inspred by the train in Hayao Miyazaki's wonderful film "Spirited Away".
Newbury - A fully-automated, N-scale, DCC layout in a macrocarpa bookcase, using sonar to start operations. (Not for sale.)
SprocketBahN - A fully-automated, N-scale, DCC, rack-rail layout in a picture frame, with a two-thirds square-foot footprint.
Wall-Mount-N - In progress... perhaps never to be finished... A funicular layout in 7cm by 135cm (2" by 53").
ANtique Coffee Table - An old, carved oak table supports an oval of track discreetly below the normal top. Fully battery operated loop of track 16" by 25" (40 by 90cm).

These layouts are in OO/HO-scale (4mm to the foot). This is the most popular scale in the world, small enough to make large layouts inside rooms of houses, large enough to have manageable dirt and contact problems. The nominal minimum turn radius is about 18" (460mm) implying a minimum circle of about 1 yard/metre diameter.

Squiffy-Waterton - A small sliver of Sodor, fits through doorways, uses one of every kind of Peco track section.

Technical Articles on Model Train Matters

What are the Elements of a Successful Model Railway Layout?

A review of Hornby Live Steam.

A review of train controllers for microlayouts.

Some information about the different model railway scales is set out here.

Projects in Model Railway Electronics

I have designed an analog PWM train controller for use with all scales. It is a pulse type, with back-EMF feedback speed regulation, can run on AC, DC or batteries, and yet is very simple and compact.

I have designed a high-performance block detector that uses chopped infrared light and an 8-pin microcontroller to provide sensitive detection in all lighting conditions.

This is my low-cost controller design, incorporating lessons learnt from using previous controllers, and offering a great improvement in price/performance ratio, the P675S train controller. Another design using an embedded microcontroller, it has inbuilt safe reversing, greatly simplified operation, and fully realistic inertia with separate braking in both shunting and cruising modes of operation. It is a fully-digital PWM type with feedback.

This is my top-of-the-line controller design in the digital PWM series, the PID684SV train controller. It has a host of special functions, including layout automation and engine armature temperature estimation. It uses a design innovation to minimise PWM-related heating problems in PWM-feedback controllers.

This is the latest and perhaps final analog train controller, one based on negative-resistance feedback control, rather than PWM. It has a host of special functions, including layout automation and all the usual things from previous models. Most importantly, it achieves excellent feedback speed control without any PWM or discontinuous current technologies. The theory of operation has been published in an EE journal.

OK, so the negative-resistance family above was not the last analog controller. This is a high-tech modification of the classic 1963 Hammant and Morgan (H&M) Clipper built into the vintage case. A great controller in a nostalgic package. I even gave it the orange power cord that belonged to the TTL Clock I built as an undergraduate in the 1970s and that lasted me 35 years.


Some early microprocessor-based controller designs:

I have designed a new analog feedback speed controller but implemented digitally using an embedded microcontroller. It is installed in the The Pizza Hill layout.

This is a prototype of a most sophistocated Z-scale train controller, based on an embedded PIC microcontroller and offering many novel features.

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