Thunder Mesa Blog

Adventures in On18

The Horse Thief & Never Mine Ry.

Plans for an On18 mining tram to feed the Thunder Mesa mainline have gone through several evolutions over the years. Most recently, I've settled on a simple point to point design that operates between Never Mine tunnel through Baxter's Butte, and some as-yet-to-be-built ore bins at Horse Thief Canyon. In between, the tram will serve the richest diggings in the territory; Big Thunder Mine and the camp of shacks and outbuildings that have sprung up around it. Earlier versions had the tram extending all the way to Calico, and even included a portable On18 module at Calico Mountain. This plan was scrapped, mostly due to esthetic reasons since I decided a long On18 trestle in front of the backdrop would detract from other scenic features there like Horse Thief Canyon and the balancing rocks beyond.

An On18 Primer

Simply stated, On18 is O scale trains running on N gauge track. The "N" in N gauge stands for 9mm, and that scales out to about 18" in 1/4" O scale. 18" was a common track gauge for mining trams in the American West so the result of this scale/gauge alchemy is On18. I'm sure that readers of this blog don't need reminding about the esoteric differences between scale and gauge, but just in case you do, there's a post on it here.

To make things just a little more complicated, On18 trackage on the Thunder Mesa layout is represented using Peco HOn30 flextrack and turnouts which are, of course, also 9mm gauge. HOn30 uses N gauge track and mechanisms to model 2' gauge or 30" prototypes in 1:87 scale - but that's a story for another day. Suffice to say that this Peco track also has the perfect look for a light On18 mining tram.

On18 uses parts and materials from N, HO, S, and O scales to represent 18" gauge equipment in 1:48. Vertical boiler engine #2, the Walter Knott uses a 3D printed shell from Shapeways atop an N scale Kato 11-103 mechanism. 

Earlier Track Plans

As mentioned above, fitting an On18 line into the world of Thunder Mesa has been an ongoing process. Several plans were created and then later set aside as the line as it currently exists evolved somewhat organically on its own. Here are a few of those On18 plans, all of which incorporate Calico in some form or another. Though none of these are presently being built, each could work on their own in some future project.

Building the Horse Thief & Never Mine

The point to point On18 HT&NM Ry runs on a level between 5 and 6 inches above the On30 tracks of the TMMC. It starts at some ore bins at Horse Thief Canyon before quickly ducking into a tunnel and emerging at Natural Arch Bridge where it crosses the TMMC mainline. From there it's on to Big Thunder Camp, which sits directly above Rainbow Caverns, and into Never Mine Tunnel which passes through the heart of Baxter's Butte. The line terminates at the combination dump trestle and loading dock above Saguaro Siding. The sharpest curve on the line is about a 12" radius and control is standard DC. In the future, point to point operations may be automated using photic detection and a Circuitron AR-2 unit.

Track and roadbed being laid through Big Thunder Camp and across Natural Arch Bridge. Midwest products HO scale cork roadbed and Peco HOn30 track were the products used.

Track was primed and painted with artists acrylics. The trestle above Saguaro Siding was originally built for On30 rails, but it works just fine for On18. The scratchbuilt jib crane is used to bring supplies up to the mines from the TMMC siding below.

Ground cover is Polyblend sanded grout, and the ballast is red dirt collected near Sedona, AZ. Plants, weeds and bushes come from Scenic Express and Woodland Scenics. Cacti are from Pegasus Scale Models. 

The miner's shack was scratchbuilt from wood and Illustration board and features flickering lantern lights.

At least two more locomotives will join the HT&NM Ry roster, a tiny Shay, and a Porter-like 0-6-0, both currently under construction. The 0-6-0 is mostly being built from scrapbox parts, but the Shay has a 3D printed shell  from Marsh Creek Miniatures and runs on a Kato 11-103 chassis.

What's Next

Most of the track for the On18 line has now been completed and the rest is details and structures. One of the main features will be the Big Thunder Mine complex. This will be a combination of kit-bashed and scratchbuilt structures sitting on a high ledge above Rainbow Caverns. A below ground view into the caverns will also reveal the main shaft of the mine and an animated lift beneath the headframe. At the Horse Thief Canyon end, ore bins and a short trestle need to be built for the transfer of ore to TMMC trains. Also, if I can find the room, there may be a small turntable and engine shops in Big Thunder Camp. 

Summing up, I was a little sad to let go of the whole Calico mini-layout idea, but part of the creative process is knowing when things just aren't going to work and making the proper adjustments. I haven' given up on Calico Mountain, far from it, it just won't be a part of the On18 layout. But there'll be much more on that in an upcoming post. 

As always, I'll do my best to answer any questions in the comments below - so ask away! Just keep in mind that the WordPress platform is a spam magnet so it may take a little while for me to weed through and get to an answer. Thanks for checking in, amigos. Adios for now!


Introducing the Carolwood & Grizzly Flats Railroad

A Tribute to Walt and Ward

The Carolwood & Grizzly Flats is a small, 38x72" HO scale, standard gauge layout inspired by the backyard railroads of Walt Disney and Ward Kimball. The layout is being built across the aisle from the TMMC and features a California, High Sierra/gold country setting themed to the late 19th century.

A Little History

In the early 1950s, Walt Disney built an elaborate 7 1/4" gauge live steam railroad in the backyard of his home in Holmby Hills, California. Dubbed the Carolwood Pacific after the street on which the Disney's lived, the pike featured a 1:8 scale 4-4-0 locomotive built by Disney Studios machinist Roger Broggie, and a complete set of freight cars and caboose built almost entirely by Disney himself. The ornate little locomotive was modeled after Central Pacific #173 and christened Lilly Belle in honor of Walt's wife, Lillian Disney.

More than a decade earlier, Disney Studios Animator and unrivaled train enthusiast, Ward Kimball had obtained some vintage full sized 3-foot gauge railroad equipment from the defunct Carson & Colorado and Nevada Central Railroads and set about restoring these items with the help of family and friends. A vintage 1881 passenger coach was joined by a Baldwin 4-6-0 locomotive that Ward and his wife Betty had saved from the scrappers torch for the princely sum of $400. In 1949, A small depot used in the Disney film So Dear to My Heart was given to the Kimballs by Walt Disney after that film finished production and Ward set about transforming the flimsily built movie set into a working structure. Ward Kimball named his backyard empire the Grizzly Flats Railroad and called it "the Scenic Line of the West," though it only traveled a few hundred feet. More rolling stock and structures were added over the years, including a second locomotive, the Chloe, and a handsome three stall engine house to compliment the 900' of narrow gauge track on their San Gabriel property.

Both of these backyard railroads were extremely influential in the development of Disneyland. The parks original locomotives were designed by scaling up and adapting plans from Walt's 1:8 scale Lilly Belle, and the Frontierland Depot was modeled after Ward's Grizzly Flats station. Legend has it that Walt even asked Ward to give him the original depot back so that he could use it at Disneyland. By then, Ward had put a lot of work into the little structure and reportedly told Walt, "Go build your own damn station!"

Today, Walt Disney's Lilly Belle and other Carolwood Pacific rolling stock rests in the care of the Walt Disney Family Museum in San Fransisco, while Disney's railroad legacy, including the original barn/workshop from Walt's Carolwood Drive home, is preserved by the Carolwood Foundation which maintains Walt's Barn and related items at Griffith Park, CA.

In his later years, Ward Kimball donated most of his collection to the Orange Empire Railway Museum in Perris, CA. His beautiful Baldwin 2-6-0, Emma Nevada, can be seen there, as well as his small plantation locomotive, the 0-4-2 Chloe. In 2007, the iconic Grizzly Flats depot, along with the water tower, were moved to John Lasseter's Justi Creek Railway, located at the Lasseter Family Winery in Glen Ellen, CA. Sadly, both structures were destroyed when wildfires swept through Sonoma County in October of 2017.

About the Layout

There can be no denying that Walt Disney and Ward Kimball were men of extraordinary imagination. Both loved trains, and both built elaborate worlds to run them in. The Carolwood & Grizzly Flats does not attempt to replicate the backyard empires of these men in a historically accurate way. Instead, it tries to hitch a ride on the same current of imagination that drove them both, conjuring the type of landscape that they perhaps imagined when joyfully operating their steam engines. So it's a miniature world of towering High Sierra peaks, deep forests, rushing rivers, creaking wooden trestles, colorful varnish, and all the bells and whistles from the early days of western railroading.

I chose HO standard gauge for the C&GF based on the availability of certain items and because Walt's Carolwood Pacific took many cues from the standard gauge Central Pacific. Ward's GFRR was strictly narrow gauge, but the truth is, once you get back into 19th century railway equipment, there really isn't as much of a size difference between standard and narrow gauge rolling stock. I also chose it because I wanted to do something a little different from my On30 Thunder Mesa Mining Co. So, different gauge, different scale, different locale.

I'm using the same "greatest hits" approach with this layout that I've been using on Thunder Mesa all these years, throwing in all of the Disney elements that appeal to me and fit the theme. Unlike Thunder Mesa, this layout will have loads of trees, mostly Ponderosa Pine to compliment it's High Sierra locale. This mountain theme also give me the chance to include many old favorites that never found a place on Thunder Mesa. In addition to Ward Kimball's Grizzly Flats, there will also be scenes that include Walt Disney's Barn, and other elements found along Disneyland's River's of America or from the good old days of Nature's Wonderland and the Mine Train. The C&GF is being built across the aisle from the On30 scale Thunder Mesa Mining Company where it can also serve as a forced-perspective background scene when photographing the larger layout.

I'm using Walther's code 83 HO track and turnouts and control will be DCC. The minimum curve radius is a tight 16" and the old-time locomotives have been tested to assure no problems. Scenery will be constructed with my usual EPF foam methods, though I might do a few plaster rock castings to get the look of High Sierra granite.

As construction progresses I'll still be taking time to work on the TMMC and the many projects that need attention there, but ideally I'd like to finish most of the C&GF within a year. Hope you'll follow along to see if I can get it done!

Adios for now!

Nature’s Wonderland, Teddy Roosevelt and the Thunder Mesa Mining Co.

Originally published April 1, 2016 on the old Thunder Mesa Blog  

In the late summer of 1906, tensions were high in Thunder Mesa Country. Mining revenues were down, and the TMMC, and its parent road, the Santa Fe, Denver & Carolwood began pushing into new territories, including those controlled by the Estrella & Sonora Grande and Calico Gold Company. Naturally, the other companies pushed back, and by August, the battle over gold and silver claims in this wild canyon country had escalated to a fever pitch. It didn't take long for rival newspapers and political gangs to get in on the fight and soon they were tossing incendiary lies and insults in all directions. Before long it was greatly feared that conditions would deteriorate into physical violence. Armed toughs from Calico and banditos from San Lorenzo were quietly being recruited by both sides and an all out range war seemed imminent.

By the fall, none other than the President himself was preparing to intervene in the fracas. Traveling by private rail car, Theodore Roosevelt just happened to be on a secret hunting trip along the fertile bottomlands of Big Thunder Creek when he was briefed on the ensuing hostilities. After quietly surveying the natural wonders of the area (and shooting a dozen elk, two bears, a catamount, a duck, two armadillo, six coyotes, and three chipmunks), our 26th president made his presence known (as the story goes, he announced his presence by shooting a shot glass off the nose of the buffalo head in Big Thunder Saloon). He called a meeting of all aggrieved parties in what came to be known as the "Council of Calico." As it turned out, the President had been thoroughly delighted by the amazing buttes, canyons, geysers, and glittering caverns of Thunder Mesa Country and had concluded that the region deserved to be protected and preserved for the enjoyment of future generations.


"Providence," said Roosevelt, "has been at work upon this land for untold ages. For here has been gathered an unmatched collection of natural curiosities and splendid scenic wonders. Verily, this "Nature's Wonderland" is an irreplaceable treasure of the United States and must be protected from the greed and petty concerns of short-sighted men."

Then, by presidential decree, he set aside the wild country on all sides of the TMMC right-of-way, excepting only existing claims, and effectively hemming-in the land hungry railroad. Invoking the newly minted Antiquities Act, and with the stroke of a pen, TR created Nature's Wonderland National Monument.

Of course, the railroads grumbled at first, but it soon became clear that the official designation and endorsement of the President himself would be a boon to the area. By 1905, the writing was on the wall as once rich finds at Calico and Big Thunder began to play out. This, in turn, had lead to the mining company's overreach into new territories already controlled by the Calico Gold Co. and Estrella & Sonora Grande. The "Roosevelt Solution" effectively put an end to the conflict while creating a rich new revenue stream for the TMMC.

TMMC management wasted no time in promoting tourism within the new monument as new excursion trains were quickly added to the schedule. Old ore gondolas were converted to carry passengers and secondhand coaches were procured from the Santa Fe, Denver and Carolwood to fill out the new trains. For its part, the SFD&C began to promote direct rail service to Thunder Mesa from Carolwood, Denver and Discovery Bay. By decade's end, tourism had replaced mining as 80% of the TMMC's revenue. In 1910, the TMMC also connected with the struggling Estrella & Sonora Grande Ry. near Lone Rock, and eventually came to control many of that line's assets.

Though the mines near Thunder Mesa were largely played out, the rich diggings around Calico continued to produce gold bearing ore well into the new century and the Calico Gold Co. remained independent until the crash of '29 forced a sale of its assets to the TMMC. Calico itself became a ghost town, and the once legendary mining camp merely another attraction for tourists aboard Thunder Mesa's colorful excursion trains.

After 1906, Theodore Roosevelt was never again seen in Thunder Mesa Country. However he did manage to visit other spectacular regions and preserve their natural wonders for future generations as well. As president, Roosevelt created five national parks and used the landmark Antiquities Act to unilaterally create 18 national monuments, including the Grand Canyon. He also set aside 51 federal bird sanctuaries, four national game refuges, and more than 100 million acres' worth of national forests.

Roosevelt's chance visit to Thunder Mesa was a classic case of the right man being in the right place at the right time. Without his wise intervention, it is doubtful that the railroad would have survived much beyond the boom times of the late 19th and early 20th centuries, and the spectacular region known as Nature's Wonderland might never have been preserved. Without Roosevelt, another chance visit by Walt Disney, Ward Kimball and Roger Broggie might never have occurred in the early 1950s, leading to a "rediscovery" of the Thunder Mesa line and sketchbooks full of ideas for a magical little park being planned for Southern California. But that legendary visit is a story for another day.

Experience Nature's Wonderland at Thunder Mesa Studio!

Enjoy the beauty and "history" of Nature's Wonderland National Monument on the Thunder Mesa Mining Company model railroad! Open Studio Days are back during Jerome's 1st Saturday Art Walk. Join us for a fun time at Thunder Mesa Studio in Jerome, AZ, Home of the Thunder Mesa Mining Co., an operating 1/4″ scale narrow gauge display featuring spectacular scenery, lights, animation, and sound. Meet local artist D.L. Meek and see what’s new on his drawing board. Stick around after 5pm for the 1st Saturday Jerome Art Walk.

Free parking at the venue and free shuttle bus service to and from downtown Jerome from 5pm to 8pm

Click here for full event info!

Open Studio & Train Day ~ Saturday, Feb 3

Open Studio Days are back during Jerome's 1st Saturday Art Walk! Join us for a fun time at Thunder Mesa Studio in Jerome, AZ. Enjoy the beauty and "history" of Nature's Wonderland National Monument on the Thunder Mesa Mining Company Model Railroad, an operating 1/4″ scale narrow gauge display featuring spectacular scenery, lights, animation, and sound. Meet local artist D.L. Meek and see what’s new on his drawing board. Stick around after 5pm for the 1st Saturday Jerome Art Walk.

Free parking at the venue and free shuttle bus service to and from downtown Jerome from 5pm to 8pm

Click here for full event info!

Open Studio & Train Day ~ Saturday, Nov 4

Join us for a fun time at Thunder Mesa Studio in Jerome, AZ. See what’s new on the Thunder Mesa Mining Company, an operating 1/4″ scale narrow gauge model railroad featuring spectacular scenery, lights, animation, and sound. Meet local artist D.L. Meek and see what’s new on his drawing board. Stick around after 5pm for the 1st Saturday Jerome Art Walk. Free popcorn and Thunder Mesa railway passes for all guests!

Free parking at the venue and free shuttle bus service to and from downtown Jerome from 5pm to 8pm.

See our events page for full details!

Train Night Preview, Free Stuff, and a Big Thank You

Hey, folks! Just a few quick announcements before I rush out the door to get ready for tonight's Open Studio. First, check out my latest video (above) from the Thunder Mesa Studio YouTube channel to see a preview of nighttime operations on the TMMC. Then, click on back here and get free MP3 downloads of the Night Sounds and Haunted Undertaker Shop soundtracks used on the layout. Just in time for Halloween!

Thunder Mesa Night Sounds Free MP3 Download

Haunted Undertaker's Shop Free MP3 Download


Free Standard Shipping Thru Oct 9 at the Thunder Mesa Spreadshirt Shop!

And for another awesome deal, visit the Thunder Mesa Studio Spreadshirt Shop and get free standard shipping on all the cool designs right up through Monday, October 9th. Just enter this code at checkout:


Thank You!

A very special "thank you" to everyone who has followed the progress of Thunder Mesa over the years, read my articles, commented on these posts and videos, sent me cool stuff, purchased my designs, or made a contribution towards the completion of the railroad. You guys are the best and I am humbled by the positive responses I have received. The layout exists to entertain and bring joy and there's much more to come. 

Happy Halloween!

Yes, I know it's still weeks away, but tonight's Open Studio will kick off the season for me and Halloween is my favorite holiday after all. The photos above were taken during last night's final lighting and effects check and that got me in the just the right mood for this spooky season. Hope to see some of you there tonight! Thanks for checking in, amigos. Adios for now!

My Latest Column in Model Railroad Hobbyist

A New Home For Thunder Mesa

My latest Imagineering column for Model Railroad Hobbyist Magazine is now available to read online.  In it, I take a detailed look at "imagineering the move" of the Thunder Mesa Mining Co. layout from my old home to my new studio in Jerome, AZ, and at prepping the space and painting the backdrop there. You can read it here: Model Railroad Hobbyist Magazine.


Open Studio and Train NIGHT – Saturday, Oct 7

Kick off the Halloween season in Jerome with our first ever Open Studio & Train NIGHT at Thunder Mesa Studio in Jerome, AZ. See night operations on the Thunder Mesa Mining Company model railroad,  and  the Moonrise in the night sky over Thunder Mesa! Experience the new Haunted Undertaker's Shop and spooky Boot Hill Graveyard. Meet local artist D.L. Meek and see what’s new on his drawing board. Stick around for the 1st Saturday Jerome Art Walk. Free Halloween treats and Thunder Mesa railway passes for all guests!

Free parking at the venue and free shuttle bus service to and from downtown Jerome from 5pm to 8pm.

See the Events Page for complete details.