Building a 16mm scale model of the largest 2-foot narrow gauge steam locomotive to operate in North America
By Ric Collins
I have been a 2 – foot narrow gauge railroad enthusiast ever since reading “The Maine Two-Footers” by Linwood Moody, published in 1959.
Over time I became interested in many of the 2-foot narrow gauge railways around the world. The first 2-foot narrow gauge railroads in the U.S. were based on the successful Ffestiniog Railway in Wales so naturally I had to see and experience the “Grand-Daddy” of all 2-footers and did just that during two trips to the UK in 1984 and 1987. For years I had watched videos and read books about the Maine Two-Footers and the Sandy River & Rangeley Lakes RR always held a special interest for me. In 1992 my wife and I vacationed in Maine to see what remained of the two-footers, including a stop at Edaville in Massachusetts. While in Franklin County, Maine we spent a great deal of time in Phillips at the local Historical Society, the Sandy River Railroad restoration park and the old rail yard where the remains of the engine house and Depot still stood. We also hiked the old SR&RL grades and stayed at the Rangeley Tavern in Rangeley which was once owned by the SR&RL.
I modeled the Sandy River in On2 Scale for over 30 years until 2003 but I initially became interested in the larger scales during the early 1990’s when LGB produced a G scale Sandy River & Rangeley Lakes electric 0-4-4T locomotive. I acquired one along with several pieces of rolling stock to operate indoors. G scale electric loco’s were interesting, but my enthusiasm perked up when I watch a friend run his alcohol fired live steam Shay on 45mm gauge track.
By 1995 I become acquainted with a company in the USA selling scale live steam models of Maine 2-foot gauge locomotives manufactured in Australia by Argyle Locomotive Works. At the time, Argyle offered a couple of Sandy River 2 Foot gauge live steam locos to operate on 32mm gauge track and I quickly decided that was the direction I had to go. My first live steam purchase was the Argyle Sandy River Mogul named “Old Star”, delivered in 1996 to our brand new garden railroad, the Mt. Greta Railway. Over the next 10 years, the MGR commissioned Argyle to custom built four additional engines for the railway.
Another view of the finished loco
For some time, I had thought about the possibility of scratch building a 16mm scale live steam locomotive and by 2006, I decided to build the Sandy River & Rangeley Lakes Railroad #23, the largest 2 foot gauge locomotive ever constructed for service in North America. It had always been one of my favorite 2-foot locomotives and in fact I had scratch-built this same locomotive in On2 scale back in the early 1970’s.
The prototype SR&RL #23 was the brain child of the chief engineer of the Maine Central Railroad which had taken over control of the SR&RL from local ownership in 1908. The Maine Central had big plans for the Sandy River which was at the time a feeder line to its own standard gauge railroad interchange yard at Farmington, ME. The MEC wanted to take maximum advantage of the increased flow of pulpwood and lumber products funneling down the Sandy River line to Farmington and to do this needed to upgrade the Sandy River’s aging fleet of locomotives. The original MEC plan called for eight (8) new heavy freight 2-6-2 engines. The specification class for this engine was to be the #23 class. Sometime later when the new specifications were sent to the Baldwin Locomotive Works, the plans were reduced to three (3) of the #23 class locomotives with road #’s 23, 24 and 25. While Baldwin was preparing the working drawings for these engines, the MEC again reduced the order to One (1) locomotive to be numbered 23. The #23 was finally assembled in October 1913 and delivered to the SR&RL in November 1913 at a cost of $7,625.00.
The real #23
Part of my decision to build this locomotive was based on my having the original Baldwin Specifications and a set of the Baldwin Locomotive Works drawings for #23. I believe that if you are going to model a prototype piece of equipment, you must have accurate drawings to work from. Some of the #23 drawings in my collection are BLW originals and some are re-drawings of original BLW drawings. The re-drawings were published in a booklet entitled the “Two – Foot Cyclopedia” Volume 2, in 1977 by William H. Jensen, Jr. Some of the original BLW drawings I have were provided by Robert Schlechter and Edward Bond. The rest were purchased from the Everett DeGloyer Library, BLW collection, in Dallas, Texas.
I studied the basic construction materials and methods used by other builders and developed a working set of specifications for the new loco, but nothing else happened for several years.
The construction of #23 did not start until after I had retired from working full time. Only then did I have the time necessary to devote to the project. Following my retirement in 2012, the 23 project did
start in earnest during the summer of 2014. While attending the National Summer Steam Up in Sacramento, CA that year I discussed the project with Rob Lenicheck, an experienced live steam narrow gauge scratch builder. Rob’s latest project at that time was a beautiful D&RGW C-25 locomotive and it was the inspiration I needed to get the 23 project going.
The first priority was to equip and set up my shop with the machine tools needed to handle the work. The last time I scratch built locomotives I still modeled in On2 and I knew my old equipment would not be heavy enough for building in 16mm or 5/8” scale. I began with a new steel work bench; a mini metal cutting band saw; and a mini-vertical mill/drill machine. We live in a retirement community, so the garage/shop space is very limited and this equipment filled the new work bench with only minor space left over for a lathe. I decided to utilize my Unimat SL1000 for the light duty machining needed and rely on the new mill for the heavy work.
The Tender
I started off first building the tender before the engine, as I needed to gain experience using the new machine tools and the tender had fewer and less critical parts to machine than the engine. After ordering a supply of steel and brass stock, I started scratch building the parts for the tender. The truck parts were machined from brass stock to match the BLW drawings. A California company, Sierra Valley Enterprises, provided the correct size of 32mm gauge fine scale wheel sets; Ozark Miniatures, Cedar City Utah provided the white metal brake shoes; Trackside Details, Pinedale, California, provided the brake hose fittings; The Train Department, New Jersey provided the gas control valve and quick disconnects; and Ron King, a good friend and expert wood worker from nearby Nevada City provided the solid Maple brake beams.
The tender trucks
The tender frame
The tank was cut out of .020” sheet brass and a NWSL Sensi-Press was used to emboss the rivet details. The tank wrapper was made in four sections to make it easier to add the rivet detail and the seams were butt joined with silver solder. Ron King provided a wood mold of the tender tank to use in forming the wrapper after the soldering. The gas tank was scratch built using copper tubing and flat plate silver soldered together and fitted into the rear of the tender tank. A spare hand operated water pump from an Accucraft Shay was provided by another local garden railroad friend, Mike Falkenstein.
Starting work on the tender body, with the water pump in place
Tender bodywork coming together
Gas tank parts
The completed tender awaiting painting
The Engine
My initial plan was to have the major flat pieces such as the chassis frames water-jet or laser cut from mild steel plate, however after working out the CAD needed with my friend and CAD expert Rich Dunn, we made the decision to design and order a couple of test parts using the 3D CAD – Metal Printing services provided by Shapeways, Inc. located at www.shapeways.com. Rich used the BLW drawings and my sketches to produce new 3D CAD drawings, starting with the frame parts needed to build the chassis.
3D printed frame parts
Some of the smaller 3D printed parts
We were very impressed with the quality of the 3D printed steel and brass parts and the speed at which Shapeways was able to deliver the parts. As the parts arrived from Shapeways, I checked them for accuracy and fit and we found the printed test parts were undersized by about 1%, therefore a 1% shrink factor was added to the 3D drawings. The additional shrink allowance corrected the problem.
After inspection the parts were machined, drilled and cleaned up as needed for assembly. I soon discovered that ordinary high speed steel tool bits would not cut through the surface of the Matte Bronze-Steel parts produced by Shapeways. It was necessary to use coated solid Carbide tool bits made for machining stainless steel. After this change, the machining progressed without problems. Ordinary HSS taps & dies in the smaller USA sizes up to 0-80 were of no use on the Matte Bronze-Steel but larger size HSS and Carbide taps would do the job if you were very careful to go slow and use a tap lubricant. I drilled the frame assembly holes clear through and used machine screws & nuts for fasteners.
3D printed rods, valve chests, covers and other parts
3D printed crossheads, chimney and other parts
The main decision for using the Matte Bronze-Steel material was the overall cost of the parts. The steel parts were about 50% of the cost of the same parts made in Raw Brass although the detail was much better with brass. I had intended to purchase the cylinders in brass based on the ease of machining and I was not sure if the Bronze-Steel cylinder bores would clean up well enough to hold steam pressure however the cost of the parts in brass convinced me to try using the Bronze-Steel instead. I will admit that boring the cylinders and drilling the steam and exhaust ports was indeed a challenge but in the end, I was satisfied with the smoothness of the bores and I cannot detect a significant difference in the operational quality of the two materials.
Cylinder blocks and smokebox saddle awaiting machining
Machining the 3D printed cylinder blocks
I prepared a specification for the wheels and contracted Walsall Model Industries, who did an excellent job providing the loco drive and pony truck wheels; counterweights; and axles. 3D printed parts were produced for the pony truck pedestals and the center pin support and all other pony truck parts were scratch built to match the BLW drawings. The driver axle boxes, driver springs and staples were scratch built from brass stock. The chassis has a fully operational equalized suspension system but also has coil springs installed on the top side of all axle boxes for added adhesion effect.
Erecting the main frames
Progress with assembling the underframe
The completed frames
Detail of the valve chests and steam connections
Fabricating the boiler was a new experience since I had never built a small scale live steam boiler before. I followed the design guide lines published by Martin Evans in his book “Model Locomotive Boilers” and Brian Wilson’s book “Steam Trains in your Garden”. I purchased a Sievert propane torch set to provide the heat required for silver soldering the large boiler. The boiler shell and smoke box is 0.065” wall x 2.50” diameter C101 seamless copper tube with 2 – 0.035” wall x 0.75” diameter C101 seamless copper burner flue tubes. The end tube plates were cut from 0.08” thick C110 copper sheet.
Preparing components for the boiler
The boiler bushings were cut, turned and threaded from 0.50” C510 Bronze round stock. The steam dome was made from 1.25” C510 Bronze round stock with a high pressure stainless steel steam line routed inside the boiler from the top of the steam dome to the steam regulator through a bushing on the backhead. The steam dome cover is a 3D printed Bronze-Steel part.
Trying the boiler in place
The top mounted sand dome is designed for use as the Hydrostatic Lubricator reservoir. A stainless steel steam line riser tube with orifice originates in the sand dome and transfers the steam oil through the SS tube inside the boiler through a bushing on the front tube sheet where it connects inside the smokebox to the stainless steel superheated steam line coming from the steam regulator to the cylinder steam chests. The sand dome lid is a 3D printed brass part threaded on the inside and fitted with an o-ring to seal the oil in and serve as the lubricator cap.
The loco coming together, with boiler and smokebox in place
The steam chests, chests covers and smokebox saddle are Bronze-Steel printed parts. The valve guide and yoke, slide valves and valve rods are scratch made. The valve rod packing glands, valve rod guides, expansion links, reverse shaft and link bearings are 3D printed brass parts. The main connecting rods, side connecting rods, reverse link rods, eccentric rod and crank and the cab reverse lever are 3D printed stainless steel parts. All rods ends have brass bushings installed.
The finished loco awaiting painting
Barring paint, #23 is ready to go
Some of the small loco fittings such as the headlight, whistle, cut lever supports and brake line fittings are castings provided by Trackside Details. The smokebox number plate and builders plates were made by MDC Plates. The Train Dept. provided the twin gas burners and jets made by Regner; and the two WeeBee safety relief valves. The air compressor is 3D printed using Bronze-Steel and the air governor is a 3D printed brass part. The side air drums were fabricated using brass tubing and the air drum/running board supports are 3D printed in brass.
The loco cab, pilot and tender tool boxes were scratch built using birch wood sheets and the cab roof is brass lined inside with birch wood and with working wood ventilator hatch. Many individual parts on the loco and the tender were scratch built using steel and brass stock because 3D Printing would have been impractical or too costly for minor parts.
The #23 loco was assembled and ready for steam trails by December 2015. Final completion and road operation took place during February and March 2016.
#23 is ready for a road test
You can see most of the parts designed by 3D Printing for the #23 project on-line at www.shapeways.com/shops.mglocoshop.
Ric Collins – Member #7760
twofootcal@gmail.com