Track Plans

Thunder Mesa Mining Co. ~ On30 Complete Plan

Revised 4/9/16

Here is the most up to date plan for the TMMC. The layout is being built in four sections with a wall mounted backdrop wrapping around three sides. Center aisle width is 36". To see the full size version of this plan: Right click > Open in new tab.

  • O Scale: 1:48 - 1/4" = 1'
  • Overall size: 15' 4"x 8' 6" plus 3' aisle at front
  • Grid spacing: 12"
  • Minimum radius: 15" at Geyser Gulch trestle
  • Mainline ruling grade: 1% 
  • Track: Peco On30 code 100
  • Control: DCC
  • Track elevation: 52" - 53" above floor
  • On18 mining tram from Big Thunder Mine to Calico: 57" - 58" above floor

Evolution of Thunder Mesa

The TMMC started out as a very simple 3' x 6' scenic display with a loop of track. Here's how plans for expanding the layout have evolved over time.

This plan was drawn up in February of 2015 and includes the On18 Calico mini-layout and 6% grade up to Big Thunder. Merging San Lorenzo with Thunder Mesa and adding a reverse loop at Calico led to the revised plan in use today.

This plan was created in October of 2014 to add Verne Niner's San Lorenzo diorama to the layout. Though workable, it's not quite there yet. The long section of hidden track along the wall is a problem and the center aisle width of 30" is just a little tight. Calico also gets very short shrift here and the decision to rethink Calico as an On18 mini-layout lead to a total redesign of this plan.

Expanded loop to loop plan with new town of Busted Flats. This plan would have operated the run up to Calico as a branch line and moved the interchange to the sleepy border town of Busted Flats. San Lorenzo takes the place of Busted Flats on the current plan.

Art studio/train room plan. This plan shows the previous location of the N scale Pagosa & Southern before it was moved/downsized to make room for an expanding TMMC.

Loop to loop design. Approximately 11' x 8.5'. 

Revisions in this area of the plan consist of adding a new switch and straight section of track to create a reverse loop. The previous hidden wye switch and return loop would be removed. 

The Calico section as revised from previous plans to include a reverse loop and a better representation of Calico Mountain.

Thunder Mesa 4' x 8' plan. This plan was created when the layout was expanded from its original 3'x6' footprint to 4'x8'. At that time an On18 tram was planned on the high line but was later switched back to On30.

Calico Gold Co. ~ On18 Plan. This plan is for a portable, 2'x5' On18 diorama that would have connected to the TMMC. Just a fairly basic loop with inspiration from Knott's Calico Mine Ride. On18 is 1:48 scale trains on N (9mm) gauge track. The On18 idea was scrapped in favor of improved operation on the On30 mainline.

Early expansion ideas. This plan was drawn to explore different ideas when I first started thinking about expanding the original 3' x 6' display.

The original 4' x 6' plan.

Calico Gold Company ~ a Portable On18 Mini-Layout

Calico was originally envisioned as an On18 feeder line for Thunder Mesa but that idea evolved into this portable mini-layout that would "plug-in" to the TMMC (see the plan from Feb 2015 above). Adding the town of Calico and a reverse loop to the On30 mainline led to the shelving of this idea. Now I've returned to the original concept with an On18 mining tram running between Big Thunder Mine and the ore bins at Calico (see most current plan at top).

The Calico section of Thunder Mesa is being built as a portable min-layout in On18. Peco HOn30 track is being used to represent On18 mine track. Minimum radius is 10" and the steepest grade is about 5%.

Concept illustration for the portable Calico Gold Company. When not on the road, the Calico layout will "dock" with the larger Thunder Mesa layout as shown in the plan at top.

Before Thunder Mesa

Below are plans for other model railroads that were started or merely dreamed about before work began on Thunder Mesa. 

Big Thunder & Western ~ On30. This plan was created for the precursor of Thunder Mesa, the Big Thunder & Western RR. Though never finished, many of the scenes and ideas for this layout have found their way on to the TMMC.

Big Thunder & Western ~ HO Scale. The first Big Thunder & Western was begun in HO standard gauge before switching to On30. This plan was loosely based on Malcom Furlow's San Juan Central.

Mine Train Thru Nature's Wonderland ~ HOn30. Long before starting on Thunder Mesa, I had seriously considered building a model of the old Disneyland Mine Train attraction in HOn30 (HO scale, 1:87 trains running on N gauge track). Those plans never got further than the drawing board but helped to plant the seed for today's Thunder Mesa layout.

More On30 Track Plans

Here are a few early plans I made when first thinking about an On30 model railroad.

This On30 plan is an L-shaped version of the old Gumstump & Snowshoe. Trains would have to be very short in order to maneuver the 4% grades and short tails on the switchbacks. The turntable-as-switch on the runaround track is a space-saving idea I've always liked and was borrowed from John Allen's Devil's Gulch & Helengon.

Here's a plan for an On30 layout in just 4x8 feet. Designed for Peco On30 track with no grades and 18" minimum radius curves. The passing siding is painfully short and I doubt that the stock pens at lower right would actually fit if the layout were built. Fun fact: Although this layout was never built, I still have a couple of cars lettered for the R&L running on Thunder Mesa today.

The GT&FC was an early On30 plan, similar in many ways to the first On30 Big Thunder & Western. This one has a more general western mountain mining theme and fits in a smaller footprint of just 8' x 6.5'. Some nice scenery potential here for a layout that could easily fit in a spare bedroom.

Here are a pair of 48" long On30 modules that could form the nucleus of an around the walls type layout. The deep canyon scene offers great scenery potential while the 4% switchback up to the mine adds some interesting operations. The removable track cassette at upper left allows for a long tail on the switchback and could also connect to staging. The minimum radius is 30". This plan would also work fine for HO scale with no changes other than the scale of structures.

This set of On30 corner modules was drawn for a friend to fit his unique space but the two end modules could easily be lengthened to a full 48 inches. A few town structures are built below the bridge along a snaking dirt road, while a large mine occupies the center of visual interest. A small station, turntable and engine house round out the scene.

For my post on N scale track plans, click here.

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