A HO scale 600mm x 600mm ‘Pizza’ model railroad layout with a simple circle, detailed mountain scenery and some interesting operational possibilities.

Micro Layouts for Ease of Moving

This HO scale micro layout was one of 3 proposed to be built to replace the Dolton / Illinook / Blue Island / Barr layout. With the possibility of an impending move some time in 2020, I decided that it would be best to minimise the layout moving stress and dismantle the previous modules in favour of some smaller and easier to move modules. The 3 micro layouts were the result, with a possible 2 more easily stored ans set up ultra-micro layouts.

Layout Description

The “Petra Pizza” is a 600mm x 600mm square (approx. 4 square feet) layout, with a single circle of track, with mountainous scenery, and very tight curves (for HO scale). It represents a small quarry branch to a small fictional town called Petra somewhere in the mountains of Maryland, USA, which is also the location of a quarry which is the main industry served by the branch and the only industry modelled on the layout.

The curves on the layout are around 11 inches on average (which means there are some parts of the circle tighter than that)! You might be tempted to think this limits the cars and locos that can run on it. Well, it does. But not as much as you might think. As far as motive power, a 4 axle Bachmann DCC Onboard EMD GP loco works ok, and the shorter wheelbase Alco S series switcher also works ok. As far as rollingstock, I have some 22 foot mineral hoppers and 40 foot open hoppers which serve the quarry, some 40 foot MOW cars which run as a tourist train, some cabooses, and some other carefully selected cars up 40 foot in length that can handle the tight curves. In November 2020, I purchased a small Plymouth ML-8 switcher specifically for use on this layout, to replace the much longer EMD GP and Alco S switchers that I had been using previously.

Plymouth ML-8 with a passenger train.


The electrics of the layout were initially very simple with just 2 wires to the track, which was wired into my DCC system. When I purchased the Plymouth ML-8, which was DCC-ready with some minor modification, I had to decide whether to add DCC to that loco. Instead of opting to add a decoder to the loco, I decided to add a DCC decoder to the layout itself. This meant that the layout could be controlled by a DCC system or a DC controller. There was very little justification for converting the ML-8 to DCC as there would only ever be one loco running at a time on the layout, and I was a bit concerned that I would botch the conversion of that loco due to space constraints in the loco. The only possible advantage would have been that the ML-8 could be used on my other DCC controlled layouts. Rather than purchase a new decoder, I removed the decoder from a loco that I hadn’t used in a long time that had developed drive train problems, so it cost nothing to add the decoder to the layout except some time.


Operating a layout that is just a circle of track might seem somewhat boring. But I have worked out a relatively interesting way of operating it none the less. A train including some open / mineral hoppers starts off somewhere on the layout away from the stone loader, representing Petra Junction, the place of interchange with a class 1 railroad. The train is started, and makes it’s way up the mountains, passing through many tunnels, for a set number of minutes, then it arrives at the Petra stone loader. At this point the train crew has to align each hopper under the stone loader so they can be loaded. Once all cars are loaded, any extra cars (eg box cars or fuel tankers) are moved to the trackside shed / depot a little way from the stone loader for unloading. Once that is done, the train starts again back to Petra Junction.

The operation of the weekly MOW cars as a tourist train is operated in a similar way, starting at the Petra Junction depot, and running to Petra depot up in the mountains. But instead of stopping for each car to be loaded under the Petra stone loader each car has to be stopped in front of the Petra depot due to the high rainfall causing undergrowth to grow just about everywhere except in front of the depot.

For some videos on construction and trains running on the Petra Pizza layout, go to the Micro Layout Videos page.

To view Blog posts related to this layout, go to the Petra Pizza Micro category.