Category: Geyser Gulch

Repairing the Erupting Geyser with a New Smoke Unit


Return to Geyser Gulch! My original smoke-unit-from-vape-pen stopped working, so I’m replacing it with a more robust and deluxe version. Step by step as I test, install, and wire up the new unit and get it working on the layout.

Mini smoke units from Etsy Seller Wayne’s Workshop

Thanks for watching, amigos!

Thunder Cam: Geyser Gulch


Howdy Folks! Over the coming months, I will be documenting every scene on the layout in these short “Thunder Cam” videos. Each one features Thunder Mesa trains passing through scenes on a typical day (or night) of operations. Supplemental music and sounds have been added where appropriate, but all else is as it might appear on a visit to the layout. As new scenes are finished on the layout, these rails fan style videos will act as supplements to the builds and projects. The ultimate goal is to chronicle the entire layout over time.


A Thunder Mesa Excursion Special


All aboard for a Grand Circle Tour thru Nature's Wonderland on this Thunder Mesa Excursion Special! Enjoy the sights and sounds along the way as we explore the Living Desert, Geyser Gulch, Rainbow Caverns, Natural Arch Bridge and more. Stops at Calico, Tumbleweed, Los Feliz Jct, and Rainbow Ridge. Apologies in advance for some unfinished scenery and empty excursion cars. Thunder Mesa is always a work in progress!

Thanks for following along, amigos. Registered users can leave questions and comments below so, please, join in the conversation!

All the best,

The Saga of Geyser Gulch – Part 3

A Scene 7 Years in the Making

I first began work on Geyser Gulch back in early 2013 and wrote a little about it on the old Thunder Mesa blog. In this three part series, I'm revisiting and elaborating on some of those old posts, and describing the planning and building of the Gulch right up to the present day. Click here to read Part 1. Click here for part 2.

Bridge footings and abutments blended into the existing scenery with Sculptamold.

Part 3: Finishing the Scene

With the trestle complete, it was time to finish the scene with ground cover, desert plants, details, and, of course, the modeled water of the hot springs and geysers. The first step was to blend the bridge abutments into the existing scenery with Sculptamold, and then paint that new scenery to match. I use flat latex and acrylic paints for my scenery painting and have a good supply of the most used colors pre-mixed and on hand.

I've described and done videos about my scenery painting techniques several times before so I won't rehash it too deeply here. Basically, I paint the new area with my scenic base coat, a special mixture of Raw Sienna flat latex house paint. Once that has dried completely, I go back and darken the textures with a thin black acrylic wash from a spray bottle or soft bush. This seeps into the cracks and crevices, darkening the shadows and giving them added depth. I allow that to dry, and then do the final scenic painting with earth toned artists' acrylics right out of the tube. I get the cheap student grade stuff since I use a lot of it. The colors used on the Gulch were raw sienna, burnt sienna, burnt umber (for deep shadows), yellow ochre, and unbleached titanium. Using a flat 1" brush or filbert, the colors are semi-dry-brushed onto the top surfaces of the rocks, working from darker to lighter tones. Colors can be blended together right on the scenery. The final step is to go back with some unbleached titanium and dry-brush on a few highlights to really make the scene pop.

Once I was happy with the scenery painting, I ballasted the approach tracks to the trestle, and started adding ground cover in the form of real rocks and dirt collected in Sedona, Arizona and Moab, Utah. This was all wetted down with a spray bottle filled with "wet water" (that's water with a coupe drops of liquid detergent to break the surface tension), and then everything was cemented in place with diluted matte medium.

Larger rocks, bushes, weeds and cacti are being added in this view. They were all cemented in place with Aleene’s Tacky Glue. Note the big rocks that have tumbled down into the water.

Fire barrels were added to the trestle refuges. These started as resin castings from Wiseman Model Services and I added the lid handles, fashioned from 1/32″ birch plywood.

Prickly pear and other cacti are castings from Pegasus Models. Other plants and weeds came from Scenic Express and Woodland Scenics.

Old Unfaithful has its own National Park style sign to alert guests to this scenic wonder. The sign artwork was created in Photoshop, combining text with realistic photo textures of real wood. 

Modeling Water in the Hot Springs

Modeling water believably is one of the biggest scenic challenges in this hobby. Perhaps one reason is that water can look so differently under varying conditions and environments. When I modeled Big Thunder Creek, for example, I wanted the look of a fast moving, high desert stream, rushing down from the high country to bring water and life to the canyons below. Frothy cascades and waterfalls give way to deep, green tinted pools, teaming with riparian plants and animals. I also wanted that green tinted water to evoke similar waterways at Disneyland. But for Geyser Gulch, I was after a very different kind of water: the travertine rimmed turquoise pools fed by hot springs and geysers.

Modeling the water for Geyser Gulch actually began with the sculpted terraces and blue-green colors applied when the scene was first begun 7 years ago. Following photos of places like Havasupai and Mammoth Hot Springs, I chose colors and textures that are not typically seen on model railroads, but nevertheless do exist in many places in the natural world. The water in these places is actually crystal clear, like the waters in a swimming pool, nearly devoid of nutrients, but filled with tiny particulates of white travertine. The amazing colors come from those sediments reflecting the sky in the clear waters.

Big Thunder Creek evokes the high desert riparian environments found in canyon country. A rare oasis of green in the red rock desert.

The turquoise waters of Geyser Gulch. In nature, the vivid colors come from white travertine sediments in the clear water that reflect the sky above. In the modeled world, they need to be recreated with paint.

As the waters evaporate, that travertine also forms a white crust on everything it comes into contact with. Over time, that's what builds those sculpted terraces. In the shorter term, it crusts the shoreline and anything close to the water. I simulated this mineral build-up on the lower parts of the trestle by dry-brushing unbleached titanium acrylics onto the stone footings, and dusting the lower bridge timbers with white chalks.

With the scene finally set, and everything painted, it was time for the final steps to make that painted on water look wet. For this, I turned to a couple of products that should be familiar to most modelers: Envirotex Lite clear epoxy resin, and Mod Podge acrylic gloss medium. Envirotex to give the water an appearance of depth, and Mod Podge to enliven the surface and make the water look like it was moving.

Follow the photos below for the step-by-step process.

It’s important to prepare the surface well before pouring liquid epoxy. Envirotex is self-leveling and will find any holes in the surface to flow through. A temporary dam of blue painters tape was used to keep the resin from flowing out of the hot springs and onto the floor.

Envirotex Lite clear 2-part epoxy resin. About 1 oz was enough to cover all of the water areas in Geyser Gulch about 1/16″ deep. You don’t really need more than that. I followed the directions and mixed the 2 parts 1:1, stirring thoroughly and pouring immediately after mixing.

After the initial pour, and as the resin began to set-up, I used a bamboo skewer to try and add some ripples to the surface. You can use a small propane torch to eliminate air bubbles at this stage also, but since I wanted the look of bubbling springs I didn’t bother with that step.

The Envirotex sets crystal clear and ultra glossy. It also wants to set completely flat and level so most of the ripples that I worked into the surface completely disappeared as the resin cured overnight. You can tint Envirotex with a drop or two of acrylic colors if you want, but since I wanted clear water, I poured the resin as is.

Dead, flat water looks pretty unconvincing in my view and will also reflect anything above the layout such as track lighting to pull you right out of the scene. The solution is to add some texture to the surface of the water and I used good old Mod Podge for this. This stuff is one of my favorite scenic materials. It’s cheap, widely available, and easy to use. The matte version even makes an excellent scenic glue.

Once the Envirotex had cured completely, I stippled Mod Podge onto the surface with a soft brush. I also brushed some onto the geyser heads and other surfaces that might be shiny from splashing water. Mod Podge is a heavy bodied acrylic medium that dries to a clear high gloss while still holding its shape.

The final look of Geyser Gulch after drying overnight. The Envirotex gives the water depth, while the Mod Podge enlivens the surface with ripples and movement.

Making Old Unfaithful Erupt

An erupting Geyser or two is something I've wanted on a model train layout since long before I even began thinking about Thunder Mesa. Inspired by "Old Unfaithful" from Disneyland's early Mine Train Thru Nature's Wonderland attraction, I wanted an effect that was reliable, relatively easy to maintain, and that could be triggered by push-button or by a passing train. I knew I wanted an effect with real steam or vapor coming out of the geyser head, but one that wouldn't damage the scenery or lead to maintenance issues over time. I had an inkling that some sort of theatrical smoke machine might work, but they were all too big and messy for my needs. To be honest, how to do the effect stumped me for quite a long time and I kind of had to wait for technology to catch up before I could do it right.


A vape pipe converted to mini smoke machine.  The plastic vial contains vape “base” – A flavorless, nicotine free concoction of propylene glycol and vegetable glycerin that is the “smoke fluid” for the machine.

As vaping gained in popularity, I began to wonder if one could modify an inexpensive vape pipe into a small smoke machine that could be used on a layout. As it turns out, you can, and I was far from the first person to think about converting one of these things to more creative and artistic uses. I wondered if you could attach a small electric fan to one end and blow the vapor out the other. After doing a little research online, I found that not only could you do that, but that the cosplay community had beaten me to the idea by several years. A few people were already making them and selling them on Etsy and other places, so, rather than cobbling something together myself, I saved a little time by purchasing one of the units and having it shipped to the studio.

I chose a model that could be activated by push-button and powered by a rechargeable 2 amp power bank via USB (not included). Then it was a fairly simple matter of hooking the unit up to the existing plumbing I had built into the geysers. Old Unfaithful was built up from carved Balsa Foam over a short length of 1/4" copper tubing that extends below the layout. Rubber tubing connects the business end of the pipe to the copper and a big red button on the layout fascia was wired up to activate the unit. The rechargeable power bank is hidden beneath the layout where it is secured to the benchwork with velcro tape. Load the unit with fluid, plug in the USB, press the button, and voila! The geyser erupts!

In this overhead view, it’s easy to see the copper tubbing inside the caldera of Old Unfaithful Geyser.

Because it’s real vapor, every “eruption” is a little different. Here, a small cloud of vapor rises from the geyser.

Check out my latest YouTube "How To" for a complete breakdown and demonstration of the system and how it works.


The mini smoke machine I used was made by MONcosplay Prop Shop, available on Etsy.

Off the top of my head, I can think of lots of other model railroading uses for a mini smoke unit like this: a forest fire scene. a slash burner at a sawmill, a burning building, a factory or smelter smokestack... You get the idea. Imagination is the only limit!

Wrapping Up

I hope everyone enjoyed this series on building Geyser Gulch and found it informative. Looking back on the 7 years it took me to complete the scene, I'm glad I didn't rush it. It certainly didn't need to take 7 years, but it does take time to build the required skills and knowledge, and to better refine an idea for the best presentation. I'll be happy to answer any questions in the comments below, or over on Thunder Mesa's Facebook page if you follow my exploits there. Remember, you can also visit Thunder Mesa Studio and see the layout in person on the first Saturday of every month. Check the Visit tab for details.

I really appreciate everyone who takes the time to follow along with my projects. Enthusiasm is contagious. Thanks for checking in, amigos. Adios for now!

The Saga of Geyser Gulch – Part 2

A Scene 7 Years in the Making

I first began work on Geyser Gulch back in early 2013 and wrote a little about it on the old Thunder Mesa blog. In this three part series, I'm revisiting and elaborating on some of those old posts, and describing the planning and building of the Gulch right up to the present day. Click here to read Part 1.

This temporary trestle bent was built to see if a bridge using lighter 8″ x 8″ posts would be convincing in the scene. It worked so well at supporting the track that the scene didn’t progress much beyond this point for nearly seven years!

Phantom Ranch Canteen, Grand Canyon National Park. Designed by Mary Elizabeth Jane Colter.

Part 2: Geyser Gulch Trestle

It's always exciting when trains cross over water and as Geyser Gulch is such a focal point on the layout it required a very special bridge. Coming up with a pleasing design was a bit of a challenge since I wanted a wooden bridge, but at the same time didn't want it to obscure or distract from the scenery in the Gulch. Then there were the purely logistical problems of engineering a trestle for a tight 15" radius curve while trying to make something that might be believable in the real world. I wanted something light and airy looking, but also sturdy.

My first design decision was to use scale 8" x 8" timbers for the posts and sills instead of the more prototypical 12" x 12"s. This reduces the "visual mass" of the bridge right away and gives a nice spindly look to the bents. The next decision was to reduce the angle of the outside posts, adding to the tall, narrow look. Next I opted for a rather unusual butterfly truss arrangement between the bents instead of the usual straight stringers which allowed for a wider spacing of the bents than would otherwise be possible on such a tight curve. This arrangement is modeled after a bridge in Franklin New Hampshire and makes for a beautiful and graceful looking trestle in my opinion.

Placing wooden timbers directly into water is never a good option and most railroads avoided it whenever possible. It might be cheeper in the short run to use a pile driver and smash the posts into the stream bed, but it's a temporary solution at best. Corrosive minerals, flash floods, and wood rot would greatly shorten the life span of such a bridge. We try to build things to last on the TMMC, so the decision was made to use footing made of local stone to support the wooden bents above the water.

Using stone rather than concrete footings was a purely aesthetic decision. I have always been a great admirer of National Park architecture, particularly the native wood and stone buildings of Mary Elizabeth Colter at Grand Canyon and other Southwestern parks. Since Nature's Wonderland shares so much in common with our National Parks, it was obvious that what I wanted was a bridge that looked like it might have been designed by Mary Colter.

With that in mind, I tried to design a bridge that would compliment and reflect its surrounding, rather than detract from them, using local Ponderosa Pine timbers from the top of Thunder Mesa and local sandstone and limestone for the footings and abutments.

Mixing light and airy construction with sturdy stone piers, this butterfly truss design requires only four bents to cross the water at Geyser Gulch. During construction, I added about a scale foot of width to the bents and widened the angles slightly, but the overall look and feel is roughly the same.

Constructing the Bridge

Planning a bridge is one thing, building it in place is another story entirely. Since I had no desire to re-lay the 15" radius curve through existing scenery on either side of the Gulch, my idea was to create the bridge deck first, then install it beneath the existing rails. Then the bents and trusses could be built and installed beneath the deck. This is a little unorthodox, but I was able to pull it off with a little help from my friends.

On real curved trestles, only the rails are actually curved, while the stringers are made up of short straight sections bolted together. Since the curve was so sharp here on Geyser Gulch, I decided to cheat a little and create a trestle that really was curved. I contacted my friend and Crescent Creek Models business partner, Jake Johnson, to find out if it would be possible to laser cut some 1/4" MDF into the shape I had in mind. We put our heads together and came up with a curved, one piece, laser cut stringer that would run the entire length of the bridge and greatly simplify construction.

I designed the one piece curved stringer with a vector drawing program (Adobe Illustrator) to perfectly match the 15″ radius of the existing curve. This was sent off to my friend Jake Johnson who had the part laser cut for me out of 1/4″ thick MDF. Once stained and detailed, the piece does a great job of simulating 12″ thick bridge stringers.

The MDF stringer and Kappler bridge ties were both stained with Minwax Dark Walnut touch-up markers. This color does a nice job of simulating creosoted timbers. I created a full size template in Adobe Illustrator for the proper placement and alignment of the ties.

Double stick tape was applied to the template to hold the ties in place. Note the longer 8×8 ties for the two refuge platforms.

Yellow carpenter’s glue was applied to the ties and then the one piece bridge stringer was clamped in place on top. This was allowed to dry overnight.

Scale 6×6 guard timbers were cut to length, stained, and then cemented in place atop the bridge ties. Grandt Line nut-bolt-washer castings were glued into predrilled holes in the tops of the guard timbers.

The trestle refuges were constructed of scale 4×4 and 2×4 stock over a quickly drawn template. The platforms are floored with scale 1×12 boards.

Before the new bridge deck could be installed, the old plastic ties had to be cut away from the Peco flextrack. Short pieces of rail were soldered to the top of the track at intervals to help keep everything in gauge.

With the plastic ties removed, the rails were painted with a Rail Brown Floquil paint marker. It’s much easier to color the rails now – before the new bridge deck is in place!

At this point I was ready to install the new bridge deck, but there was a small problem. I wanted to use Micro Engineering small spikes for a prototypical look on the bridge but I was completely out of them. To make matters worse, they were also out of stock at all of my usual suppliers. Once again, a friend came to the rescue. Tom Gazsi said he had some small spikes that he'd been holding onto since the early 70's and offered to put them in the mail for me right away. They arrived in a couple days and the TMMC bridge crews were back in business. Many thanks Tom!

Before spiking, contact cement was applied to the bottom of the rails and allowed to dry. Then the deck was held snugly in place with foam blocks while the glue was reactivated with a hot soldering iron. This makes for a tidy job.

Pilot holes were drilled with a #75 bit in a pin vice and the spikes were pushed into place with a Xuron rail spiking tool. The small wooden block also helps keep the rails in gauge during spiking.

Each tie on the trestle gets 4 spikes. It’s time consuming, but the final look is well worth the effort.

The bridge abutments and footings were carved from Balsa Foam and painted with artists’ acrylics. Grout between the rocks is spackling compound pressed into the nooks and crannies.

I created a jig to make construction of the bents easier. A scale drawing was laminated to foamcore then covered with clear packaging tape. The foamcore allows you to hold things in place with pins while the glue dries, and the tape ensures parts wont get glued to the template.

One of the completed bents. Careful measurements were required to maintain a correct height for the carved Balsa Foam footings. Grandt Line NBW’s were painted dark brown and applied in logical places.

Each bent was carefully cemented in its proper location beneath the trestle deck. Then the butterfly truss braces were custom cut and fitted for each bent. An abbreviated version of the jig above was used to build the short bent near the left end of the trestle.

With all of the bents and truss supports in place, the final footings and abutments could be added and blended into the existing scenery with Sculptamold.

With the bridge now complete, the next steps were to blend it into the existing scenery and finish the Gulch itself. I'll cover all of that and more in part 3 of this series. We'll look at ground cover, plants, and details; and do some final water modeling with clear epoxy resin to make those travertine pools come alive. I'll also show how I created the effect of an erupting geyser in model form. Stay tuned, amigos! Adios for now.

Click here to read Part 3.

The Saga of Geyser Gulch – Part 1

A Scene 7 Years in the Making

Way back in early 2013, I first described the area called Geyser Gulch on the original Thunder Mesa blog:

"Just after leaving Thunder Mesa, trains pass beneath majestic McKennon Arch, gateway to the Living Desert, and into an active geothermal area known locally as Geyser Gulch. The Gulch is spanned by a rickety old wooden trestle and is home to bubbling pools, multi-hued hot springs and more than a couple erupting geysers - including "Old Unfaithful," most famous of them all."

In this three part series, I'll revisit some of those old posts, and describe the planning and building of the Gulch right up to the present day. Along the way, I'll detail the planning process and techniques used to bring this scene to life.

Geyser Gulch was always planned as a signature scene on the Thunder Mesa layout, with the greatest vertical separation on the railroad; 33 inches or 132 scale feet from the bottom of the Gulch to the top of Baxter's Butte. While it has taken seven years for me to complete the scene, It didn't really need to. That's just the way it worked out, with other projects and interests cropping up and demanding attention along the way.

Follow along to see how it all came together!

Part 1: Building the Gulch

Inspiration for Geyser Gulch and its deep turquoise travertine pools came from several sources, not the least of which are similar scenes at Disney parks. The original Mine Train Thru Nature's Wonderland at Disneyland had an area with erupting geysers and bubbling mud pots, including "Old Unfaithful Geyser" that would erupt and mist riders as the mine trains passed. Then there are the hot springs and erupting geysers on the Big Thunder attractions at the Magic Kingdom in Walt Disney World and Tokyo Disneyland. Grizzly River Run at Disney California Adventure has an active geyser area that the rafts pass through, and there are similar scenes along the railroad at Disneyland Paris, and at Grizzly Gulch in Hong Kong Disneyland.

Equally important is where the real world inspiration for these Imagineered scenes came from; places like Yellowstone and Grand Canyon National Parks. My Geyser Gulch scene is based mostly on Mammoth Hot Springs at Yellowstone, and the colors of Havasupai at Grand Canyon.

Old Unfaithful erupting on the Mine Train Thru Nature’s Wonderland at Disneyland. Circa 1960. 

Hot Springs and erupting Geysers on the Big Thunder Mountain Railroad at the Magic Kingdom, Walt Disney World.

Creating a Natural Wonder

Geyser Gulch represents the essence of my modeling philosophy as it pertains to Thunder Mesa: Don't be boring. The truth about real railroads is that vast stretches of them are indeed boring or monotonous. If I wanted to be realistic I would focus on those mundane realities, but a strict adherence to realism has never been my goal. I want to create an immersive, wondrous world, with just enough realism salted in to make it believable. No real railroad would build their line beneath natural arches and over active geothermal areas, but this is the "Nature's Wonderland Route," so we pass from one scenic wonder to the next with all of the boring parts cut out.

The scene occupies an inside corner of the layout with one of the sharpest curves on the entire line. Trains pass through McKennon Arch and transition to the new scene on a 15" radius curve. The scenery drops away below track level as Baxter's Butte soars high above, creating some of the most dramatic vertical separation on the railroad. But in the beginning, it was just plywood and Extruded Polystyrene Foam (EPF).

The basic shape of the Gulch was built up with 1″ pink EPF carved with a hot-wire cutting tool.

The terraced hot springs were built up with disks of foamcore, card-stock and paper, cemented into place with white glue.

1/4″ copper tubing serves as plumbing for the geyser heads. This will connect to a mini smoke machine below the layout. “Old Unfaithful” was carved from Balsa Foam.

The EPF foam layers were smoothed and blended together with Sculptamold. Rock detail was carved into the Sculptamold as it set.

Liquitex acrylic modeling paste was used to shape and detail the edges of the travertine terraces.

Once the Sculptamold and modeling paste was dry, the entire scene was painted with the scenic base color, Raw Sienna. I use acrylic or latex paints for this.

The areas around the hot springs and geysers were darkened with acrylic paint, and the first turquoise tones were added to the travertine pools.

Raw Sienna, Burnt Sienna, Yellow Ochre, and Unbleached Titanium acrylics were used to finish the rock colors and create the look of years of mineral staining from the springs.

The travertine pools were painted with mixtures of turquoise acrylic paints, mixed to match the colors I have observed at Havasupai in Grand Canyon and other locations around the Southwest. Colors were blended together in place with a soft brush to give the look of churning and bubbling springs.

At this stage, progress on the Gulch was delayed for several years as work, many other projects, and an eventual move of the entire layout to my new studio in Jerome kept the project simmering on the back burner. Recently, work on the Gulch has resumed, and in part 2 of this series, I'll dive into the planning and construction of Geyser Gulch Trestle. Then, in part 3, we'll finish the Gulch with liquid epoxy resin, ground-cover, plants and details, and finally see Old Unfaithful erupt!

Thanks for coming along for the ride, amigos. Adios for now!

Click here to read part 2.