Arizona
Model Railroading
Society

Welcome to the ‘HO’ Scale Division

The HO layout represents railroading in Southern Arizona in the mid 1950. Our modeling covers mostly Southern Pacific mainline railroading with some Sante Fe based industrial modeling at Mobest in downtown Phoenix. Of course, many details have been omitted or “selectively compressed” to fit the desired features into our layout space.

The track plan of the entire layout is available in the HO Switchman's Time Table. This document also contains the HO Division Operating Rules. The document when printed is meant to be printed on both sides of the paper and folded into a pamphlet.

Our journey begins on the mainline in Yuma. Traveling twice around the layout will bring you through scenic locations representing Mohawk, just east of Yuma with its citrus orchards and quaint western buildings. Rounding the bend and through the tunnel, a train travels through the “Esses” adjacent to the red cliffs heading for Magma and the interchange with the Copper Basin Railway and it’s connection to the smelter at Hayden and the Ray Mine.

After the Magma Interchange, the rear mainline highballs through the desert in Sentinel, headed for the PFE (Pacific Fruit Express) yard in Gila Bend. As you enter Gila Bend there is the diesel engine facility for refueling and repairs. After leaving Gila Bend, trains eventually go under the Irene bridge on their way to Phoenix. The engine service facilities in Phoenix service both Phoenix and Yuma, due to the quirk of twice around railroading. Continuing east out of Phoenix, you will pass through the real railroad towns of Maricopa, home of the Cowtown Feed Lots, and Casa Grande, home of Frito Lay and our model of Coxan’s Lumber and the Casa Grande Station. Leaving Casa Grande, you will arrive in Tucson, our largest yard facility where many large trains can be sorted for their various destinations both on and off the layout.

Leaving Tucson heading eastbound, you will pass the large turntable with its 1950ish roundhouse (currently under construction) on the way to the small mining districts of Silver Bell and Superior and finally reach our layout’s central scenic view of the Irene Bridge near Vail Arizona. This model is an accurate representation of the location east of Tucson where the old Southern Pacific #1 and #2 Mainlines cross at Cienega Creek. The real bridge today is located in a Pinal County Park where you can hike and enjoy the trains and wildflowers.

At the lower level below Casa Grande, you will notice staging tracks that serve to enable members to put their trains on and off the layout safely. During operating sessions, these tracks represent distant cities that are located off the layout such as El Paso and Los Angeles, increasing operating possibilities.

The HO layout is approximately 50 feet by 20 feet in the shape of a "H". The twice around single track mainline is approximately 200 feet long and in the basic figure 8 configuration folded over itself with alternate routes. Three independent loops are possible for running during public event shows. The Tucson yard is large and can accomodate trains of 40 to 50 cars (based on 40 and 50 foot cars). There is also a yard in Phoenix and PFE. Phoenix has a turntable used for turning engines. In addition, there is a large staging yard that represents Los Angeles to the West and El Paso, Texas to the East. The minimum mainline radius is 36 inches with branch lines having a minium 18 inch radius. The track is mostly code 83 nickel-silver flex track. Turnouts are a combination of Peco, Shinohara, and hand built (Phoenix and Tucson yards). The minimum mainline line turnout is a #8. All other turnouts are a #6. Turnouts are controlled with momentary switches on panels along the side of the layout. Most of the turnouts are controlled by slow motion switch machines.

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Our trains are controlled with a Digitrax Digital Command Control System (DCC). With this system, each locomotive has an electronic decoder and is addressed independently from all other locomotives on the layout. In this way, maximum realism is achieved by enabling each model engineer to control his train, rather than the layout, just as on a real railroad. The layout is divided into power districts providing short-circuit isolation between the power districts. Power districts prevent shorts on the layout from bringing the entire layout to a dead stop. Auto reversers are used to keep track polarity straight when entering and exiting reverse loops. One Digitrak command station and three Digitrak boosters supply all the smarts and power for the entire layout. Our engineers use radio controlled throttles for driving their trains and communicating with the DCC system via Loconet jacks provided on the side of the layout.

The basis for the scenery is mostly foam with a layer of watered down drywall mud. The mountain scenes are painted in the desert colors of Arizona. Most of our effort is currently concentrated on scenery.