Locomotive and tender

Scroll to the bottom to see the day-by-day process of adding DCC, details and paint in 2014 with periodic updates in later years

A. Description: 3700 class, oil burner, without stack modifications for tunnels

B. Name/number: 3746 (as equipped between March 1939 and June 1949)

C. HO model: Sunset, brass


This Sunset ATSF 3700 class brass engine appears to be unused and original from the 1976 production run per the notes on P. 75 of The Illustrated Guide to Santa Fe HO Brass Steam Locomotive Models, Redding and Baker. The red color transferred from the foam to the model but it won’t be a problem for me as I will be stripping and painting it.


The Balboa brass engine shown above is a “nonesuch” model without a prototype; it has 63″ drivers instead of the correct 69″ ones as well as other inaccuracies. I originally thought that it wouldn’t bother me but it did so I’ve since sold it.

D. Details to be added to the model: correction of minor inaccuracies, DCC, operating headlight, paint, lettering and light weathering.

E. Major references: Iron Horses of the Santa Fe, Worley; “Santa Fe’s 3700 Class 4-8-2s,” Kistler, SFRH&MS Warbonnet, 4th Qtr. 1998; Santa Fe 3700 Class 4-8-2 Mountain Pictorial, Ainsworth & Karam, Jr.; photo of 3743 with tender right-rear view, P. 165, Steel Rails Through California, Kistler; other photos from the Western Archives of the Santa Fe Railway Historical & Modeling Society.

December 10, 2014

Day 1 of a one-month project to add DCC and paint to the Sunset locomotive

1. Determine what I have and what I need (subject to change as the project progresses)

Have: engine/tender; Tsunami TSU-1000 decoder; Easy Lift Off paint remover; Floquil (red label) Primer, Engine Black, Grimy Black, Glaze, Crystal-Cote, Flat Finish and many other colors/kinds of paint for details and weathering; decals (Microscale 87-64 engine and 87-363 tender); variety of LEDs, bulbs and MV lenses for lighting; cab curtains (Rio Grande Models #3552); crew figures

Need: micro plugs/sockets, larger speaker instead of the DLG8, SoundTraxx CurrentKeeper (keep-alive device), determine/obtain correct thinner for Floquil red label, MEK (in case the Easy Lift Off paint remover is not effective)

2. Make a plan (subject to change as the project progresses)

Operate loco and tender on DC power, fix any mechanical problems

Dissassemble loco and tender, determine locations of items to be added, electrically isolate motor from frame, modify for speaker, modify for light(s), add weight if there is space

Test decoder, speaker, lights, etc.

Strip paint

Add detail parts that need to be soldered in place, if any

Prepare for paint

Paint major items

Install electronics and test

Paint/detail/install minor items

3. Resources

A Beginners Guide to Installing DCC Decoders by Mark Schutzer, free pdf download of a 2014 PCR/NMRA convention clinic http://markschutzer.com/ go to “Clinics” in the left column of the linked page then click on the clinic title

How to Paint a Steam Locomotive by Jeff Johnston, DVD set  http://trainvideosandparts.com/paint-a-model-train.html

See References above.

Day 2

Cleaned up my work area. Ran the loco on a 22″ radius snap track circle on the floor — it hesitated a bit and is excessively noisy. I hope that the problem is just dirty rail/wheels and a lack of lubrication. Downloaded and started to read this brass troubleshooting tutorial: markschutzer.com/…ics/TroubleshootingBrass2008a.pdf .

Day 3

Dissassembled tender and measured it for component space.

Ordered railmaster.com DHB28-Box 2 watt 8 ohm 28mm speaker w/enclosure.

Test-fitted an MV LS200 lens on the warning light on the rear of the tender. Warning light will not be functional.
Test-fitted a Kadee coupler box using the provided Sunset screws.

Spent hours researching what road number and modifications are needed. Decided on 3746 between March 1939 and June 1949 based on the Major Visual Modifications Made to 3700s chart by Stan Kistler on Pp. 22-23, Fourth Quarter 1998, The Warbonnet (publication of the Santa Fe Historical & Modeling Society), Illustrated Guide to Santa Fe HO Brass Steam Locomotive Models by Redding and Baker, and the 3rd Rail review noted below.

Details to be done on tender:

  • Revise shapes of the front of oil bunker and add tool boxes, etc.
  • The front portion of the 15K oil tender is completely wrong. Images of how it should look, and other comments, are in this review of the O scale model  by 3rd Rail (Sunset): http://www.3rdrail.com/sf3700-review.html
  • Add off-center step on rear of oil bunker
  • Add passenger car buffer above coupler
  • Drill scupper drain holes

Details to be done on locomotive:

  • Add air hose protection plate on pilot
  • Add cab curtains
  • Add functional headlight bulb or LED and lens
  • Add simulated classification lamp lenses
  • Add cab window glass

Day 4

Looked for photos and/or drawings of the front of the 15K tender without result.

Looked for commercial detail parts to revise the front of the oil bunker without result.


Removed the running gear from the superstructure. The tube between the motor and gear box is rock hard and beginning to crack — it’s supposed to be flexible.

Day 5

Removed gear box. Gear lube wasn’t hardened or gummy. At some later time I’ll clean the gears and put in fresh grease.

The drivers rotate freely with no binding problems. They aren’t as free-spinning as I would like. At some later time I’ll wash out the axle bearings with naphtha and add fresh oil.

I have photographed the frame from several angles before disassembly and will continue during the process. As I remove parts I make a simple drawing showing the screw locations then place the part(s) into labeled containers.

Ordered a CurrentKeeper and an 8-pin NMRA plug/socket connector.

Day 6

Closely examined the interior of the superstructure. It looks like there will be enough room for the boiler weight and the DCC electronics. Headlight bulb/LED installation will be difficult because there is a space between the back of the headlight and the smokebox door. I am not going to drill a hole straight through and have the wiring visible.

Day 7

Studied a NWSL 485-6 Universal Coupler set that I happened to have. It looks like I can make it work on the 2.0mm motor and gear box shafts.

Day 8

Removed the oil bunker from the tender body and placed both, along with the frame, in an old loaf pan. Some previously used Polly Scale Easy Lift Off paint remover was brushed on. Within an hour the red color from the foam was gone. After 4-1/2 hours there was no further paint removal so I discarded the liquid, washed the parts with water and applied fresh E.L.O. After four hours with a little brushing every hour or so, there was no progress so I rinsed it off. E.L.O. works really well on more-recently applied paint but for this case I’ll have to try again with something stronger. I’m trying to use the most-benign solvents that I can but I expect that this will require acetone or MEK to strip the paint.

Studied the NWSL U-joint instructions, made a rough drawing and carefully cut and chamfered the motor and gearbox shafts leaving a 6.5mm gap. Here’s a photo of me cutting off part of the motor shaft — sparks are shooting off to the lower left. Masking tape keeps particles from getting into the motor and running gear.

Disassembled the gearbox and soaked the parts and the gear on the driver axle in Goo Gone Spray Gel. After about twenty minutes I scrubbed off the gunk with an old toothbrush. I then cleaned them in dishwashing detergent and a thorough water rinse. The loco running gear was dried off with compressed air. I reassembled the worm and idler gears and closed up the case after lubing the bushings with a little Labelle 108 lubricating oil and the gear teeth with Labelle 102 gear oil.

The CurrentKeeper and 8-pin NMRA connectors arrived. I had thought that the connectors would be two pairs of plugs and sockets but they turned out to be four plugs and no sockets. It’s time to go shopping again. I ordered a bunch of 40-pin S5800-40-ND plugs and S5751-40-ND sockets from Digi-Key. They can be broken into smaller units for as few or as many pins as needed. If the sockets match the pins on the NMRA plugs then I’ll glue two rows of four together.

Day 9

No work on the project today. My collection of electrical/electronic parts has made it difficult to find things so I started organizing and downsizing. The contents of two overstuffed 10″ x 12″ x 2″ drawers will expand into a third. I’m dumping unneccesary space hogs like low-quality open-frame motors and a pair of used Tenshodo solenoid switch machines. I’ll keep a new-in-the-package potentiometer but I’m not sure why. Some of this stuff is so old they have price tags like a 5-pack of resistors for 39 cents.

Day 10

Continued organizing the electrical stuff, including more from other places. Now it will be easy to root through just LEDs or bulbs or plugs/sockets, etc.

Used fresh acetone as a paint remover on the tender parts. I didn’t have enough acetone to completely immerse the parts so I kept them wet by using an old toothbrush two or three times an hour. Safety protection included wearing a respirator and 5 mil nitrile gloves with all work done outdoors away from ignition sources and burnable materials. The E.L.O. from the previous attempt took off the outer layer of paint. About four hours of acetone today removed most, but not all, of the rest. I won’t be attempting to remove any more paint from the tender.

Read some tips on inspecting a brass engine, removing paint and repainting from an online forum here:

To see them, scroll down past some not-so-useful forum comments to read the posts by nobullchitbids on October 5, 2005. He recommends acetone as a paint remover.

Day 11

No work on the project today. I volunteered at the Santa Fe archives during the day and went to a holiday dinner/party afterward. The railmaster.com DHB28-Box 2 watt 8 ohm 28mm speaker arrived and fits with plenty of clearance in the tender.

Day 12

Bought a gallon of acetone, filled an empty instant coffee bottle and dropped in the superstructure. There was room for the tender parts, too, so I put them in despite earlier having decided that they had been stripped enough.

Unsoldered the black wire from the motor mount and removed the motor from the loco frame.
Applied black electrical tape to the bottom of the motor. The motor shell shouldn’t have any current flowing through it so the tape is probably unnecessary but it’s an easy way to insulate it from the loco frame.

Put a drop of Labelle 108 oil on the front and rear motor bushings, spun it by hand then blotted up the excess.

Pressed one of the NWSL U-joint fittings onto the motor shaft. The other fittings are for shafts smaller than 2mm so I enlarged one very slowly with a round file then pressed it onto the gearbox shaft. Both fittings got a drop of superglue, just in case, on the ends away from the U-joints.

Styrene .010″ insulators were cut and super-glued to the motor mounts. A thin film of Shoe Goo was applied and the motor attached to the mounts. Styrene rods replaced the three metal screws that originally attached the motor to the mounts. There is no chance of any electricity getting to the motor except via the wires. The motor/mount unit will be removable because the screws attaching the mounts to the frame will still be used.

Installed the gearbox after putting a drop of gear oil on the driver gear.

Made a torque arm, per the Mark Schutzer online clinic, of 0.015″ brass x 5mm wide. I attached it with Shoe Goo, unlike the clinic instructions, instead of screws. I was careful to only glue it to one half of the gearbox so the box can be disassembled in the future. The arm’s purpose is to keep the motor and gearbox aligned but still allow some movement. The arm is necessary when using U-joints.

It runs! After the Shoe Goo had set up for about twenty minutes I ran it at low RPMs and am very pleased with how quiet it is.

Scroll down to Feb. 10, 2016 and Oct. 17, 2016 to see revisions to gearbox and torque arm.

Day 13

No work on the project today. The brass parts, except for the frame/running gear, are still submerged in acetone. The 40-pin plugs/sockets from Digi-Key arrived and look to be very useful. Their sockets don’t match up with the spacing on the NMRA 8-pin plugs, though.

The Shoe Goo on the motor mount and torque arm has set up for 24 hours and all seems to be well. I ran it in both directions at high speed and operation still seems fine. I don’t want to run it too much because the axle bearings, rod bearings, etc. probably haven’t been oiled since it was new in 1976. I’ll clean out the old lubricants, paint it and then oil it before I run it seriously. But before that, I’ll need to get the DCC and other electrical items installed on a trial basis.

Day 14

Soldered a tiny non-functional linkage on the valve gear mechanism. Apparently it wasn’t securely attached at the factory and came off a few days ago while I was handling the frame/running gear. Removed the motor’s red wire connection to the drawbar and removed the drawbar.

Day 15

Pulled the tender and superstructure parts from the acetone then brushed them off while wet. There were not any obvious layers of paint coming off but solder joints were visible. The parts were submerged for about 70 hours (far longer than needed but it was more convenient for me to leave them in).

Removed brakes and trailing truck from the frame.

Removed the motor-gearbox unit. I discovered that the rear motor mount was soldered to the frame so I had to pull the styrene rod and separate the Shoe Goo bond on the back of the motor to remove it.

Cut and bent coat hanger wire to fit through the drawbar hole. Suspended the frame in a partial jar of acetone up to the tires on the front drivers.  Used a rubber band to hold plastic wrap on the top of the jar to minimize evaporation.

Test fitted the larger diameter (two sizes are in the set) MV lens LS 8 for the headlight.

Unsoldered tender details to be replaced or re-located. Began cutting away material to make the front area of the tender more accurate. The oil bunker is a separate part so it makes working on it much easier than if it was soldered to the tender. More will need to be cut away before I start making the filler pieces.

Day 16

Vigorously brushed the front portion that had been submerged in acetone. Solder joints could be seen on some parts but the steam chests seemed to be unaffected. Put it back in the solvent.

Pulled it out after 30 hours and brushed the areas again but it didn’t look like any additional paint had been removed. Added more acetone to the bottle to cover all of the drivers. I swished the frame around in it and manually rotated the drivers to wash out oil from the axles and rods.

Replaced the .010″ styrene spacer on the rear motor mount. The first one was  melted by the acetone fumes.

Resoldered a front cut lever bracket that came loose.

Glued a tiny piece of brass shim stock onto the pilot for the air hose protection plate. Its purpose on the real ones is to keep the air hose ends from falling between the bars on the pilot.

Day 17

On the tender, resoldered one of the brackets that attaches the tender shell to the frame. Unsoldered and removed the footplate supports and cut away more material on the front to prepare for changing it to look more accurate. I’m a modeler, not a collector, so I don’t have any qualms about making modifications that have probably reduced its value greatly.

On the loco, cut back the mounting tab on the front coupler box and glued .010″ styrene to the mounting areas to electrically insulate the box from the frame.

Day 18


Soldered a brass strip under the holes of removed items on the top of the oil bunker. This will be a backer for filling in the holes.


Added .005″ and .010″ styrene to further insulate the coupler box and also to insulate the coupler within the box. The coupler is now non-functional as I have attached it with Shoe Goo and deleted its screw and linkage. I also added .010″ styrene strips to the lower part of the pilot. All of this is to prevent shorts in case my pilot should touch both rails or the front coupler should contact the coupler of something not isolated from the rails. Used an ohm meter to confirm the isolation.

My glacier-like pace doesn’t bode well for finishing this project within a month of starting. I hadn’t anticipated spending so much time on electrical isolation nor restyling the tender.

Day 19

Measured and drilled holes in the tender floor for the speaker. This should have been a pretty straightforward task but it wasn’t. After drawing pencil lines on the underside to avoid the frame and sills I center punched the starting point for each hole. After a couple of gentle whacks one of the toolboxes came off. Well, maybe it had a weak solder joint. A few whacks more and the other toolbox came off, too. I drilled pilot holes but had to go slowly because I didn’t want the heat to cause any problems. I then drilled the 21 1/8″ diameter holes in bunches of about five at a time, again going slow because of the heat. There were a lot of burrs on both sides of the floor. It was easy to smooth them off on one side with a big flat file. The burrs on the bottom side were difficult to get to because of the frame, sills and other items so I used a reverse-cone tool in a motor tool to smooth them off as best I could then wire brushed them with the motor tool. It doesn’t look as nice as I would like, especially since the holes are a bit out of alignment but I don’t expect that many people will see them so there’s no point in trying to improve the appearance.

Day 20

No work on the project today. Monkeyed around with some circuit boards from battery-powered flickering LED holiday “candles.”  The circuit might be useful for a firebox light under the loco powered by the DCC unit.

Day 21


Was not successful in re-soldering the tender toolboxes in place. I was concerned about too much heat causing other problems so I attached them with 5-minute epoxy. You can see the tool marks around the speaker holes mentioned earlier. I might smooth them out a little more but they won’t be very visible after being painted flat black.


Started cutting and bending .015″ brass sheet to fit onto the tender. I cut it to the height, bent it around a 1/8″ drill bit then trimmed the ends to fit. I left the old coal doors in place because they add a lot of strength and won’t be seen.

Day 22


Made the brass piece for the fireman’s side of the water tank then soldered both in place. I don’t have much experience in metalworking so it was a struggle but it came out well enough. It was difficult to make the butt joints. The parts are solidly attached, as they include a “wing” that is soldered to the underside of the top of the water tank that provides a lot of rigidity. The gaps will be filled at a later date.

Day 23


Cut a piece of .015″ brass to the height needed then bent it around a 1/8″ drill bit in two places. Removed material from the tender body and oil bunker. Cut slots into the tender to match up with the brass “U.” Did a lot of minor bending and filing to get the parts to fit reasonably well. The “F” written on the inside of the “U” indicates the fireman’s side. Unseen is an “E” for the engineer’s side. This keeps me from incorrectly installing the part during the tedious trial-and-error process of fitting.


Soldered the top of the “U” to the oil bunker then roughly filed the bunker to match the shape of the new piece. At this stage it is important to keep the oil bunker removable.

Day 24

Opened up two large holes in the top of the water tank under the oil bunker. These won’t be seen but will prevent the oil bunker from being a closed compartment after it is soldered in place. Drilled a 1/8″ hole in the front of the “U” that will later be covered by the sand box (for sanding flues). It’s important to not have closed compartments. When the tender is being prepared to be painted, water or other liquids could get into the compartments and be difficult to drain or evaporate.

Day 25

No work on the project today.

Day 26


Cut out and soldered two brass panels and filled holes in the top of the oil bunker.

Day 27

Read an excellent article by R.G. “Bob” Battles (Pp. 104-113, Model Railroad Hobbyist, Dec. 2013*) on installing DCC. He recommends doing a stall current test on the motor. I don’t have an ammeter that reads higher than 200mA so I’ll get one. I would expect that the can motor wouldn’t draw more current than the Tsunami is designed for but it would be best to check. Bob goes through all the steps needed to install DCC and he gives a lot of space to properly soldering fine wires and connectors. I’ll be referring to his article as I progress.

Didn’t work on the project today — have been reading the January issue of Model Railroad Hobbyist that was published today.

*Can be downloaded free at http://model-railroad-hobbyist.com/magazine/back-issues

Day 28

Laid out locations of handrail stanchions and the forward oil hatch that were removed on Day 15. Drilled pilot holes for the stanchions.

Day 29


Opened up the holes to fit the stanchion bases that were removed earlier. Filed and sanded the tender parts to minimize tool marks. Soldered the footboard supports (removed earlier) in new outboard positions. The slots at their original inboard position will be covered later. Soldered the sand box to the front of the oil bunker.

Day 30

Soldered the oil hatch in its new location farther forward on the top of the oil bunker. Bent and soldered one steam line to the (yet to be made) oil bunker heater. I won’t be including unions, elbows, valves, etc. on the added lines and conduits.

Day 31

My one month goal to finish this project is up today. Obviously, it’s not even close to being ready for paint, let alone DCC. I’ll keep plugging away at it. Redid yesterday’s steam heater line and added a second one but neither look right. Bent and soldered a brass wire onto the oil bunker to represent the electrical conduit for the warning light but it’s not right either. Bending and placing the wire in position isn’t too difficult but somehow during soldering they move without my realizing it. Probably the best modeling skill to have is knowing when to stop so I’m finished for today. I’ll have to remove all of it, clean up the surface, bend new ones and try again next time.

Day 32

Removed the brass wire details from the tender oil bunker. Made and soldered new ones — looks good! I also heated up the solder joint on the relocated forward oil hatch and straightened it.

Day 33


On the water tank, bent and soldered brass wire to represent the electrical conduit to the warning light. The red arrows show this along with the items mentioned in days 31 and 32. I’ve had enough of brass work for awhile. I’m more comfortable with building in styrene so that’s how I’ll do most of the rest of the additions to the tender such as the upper tool boxes.

Day 34

No work on the project today. Read Andy Sperendeo’s article, “Painting a brass steam locomotive,” on Pp. 146-149 of Model Railroader, Nov. 1986 where he uses a Santa Fe 3156 as an example. He has lots of good techniques although I won’t be following his instruction to drill through the free-standing headlight and smokebox for the headlight wiring.

Day 35

Cut off a pair of plugs/sockets and soldered them to the two purple wires from the DCC unit and the two speaker wires.

Day 36

Installed the boiler weight. Unsoldered the brass wires representing the whistle and bell cords. Removed the smokebox door — until I inspected it closely I thought that it was permanently attached. The hand rails and simulated headlight cable on the front are press fits so after carefully pulling them out I pried open the smokebox door and it came off easily. This will make painting easier as only the door (not the entire smokebox) will be Tarpon Gray.


Started a pilot hole into the bottom of the headlight/bracket with a #72 bit in a pin vise then switched to a 1/32″. The red arrow points to a second 1/32″ hole drilled through the smokebox door. After painting I’ll install the 1.5 volt bulb and pull the wires tight so that they will be nearly invisible. Note the empty space between the headlight and the smokebox door — I wouldn’t want wires visible there. Inside the loco shell there will be a resistor to reduce the voltage coming to the bulb from the DCC unit.

Day 37

Loosened the sideframes of the tender trucks and removed the wheels/axles to clean up for painting. Scratched an “F” and an “R” onto the tender truck frames to designate “front” and “rear” and also scratched “I” letters into the sides that had insulated wheels.
Modified a well-used Modelers Choice #233 wheel painting mask. As made, it’s a nice mask for holding the parts but I’ve been irritated every time I’ve used it because it doesn’t allow even painting from all angles. It’s also awkward to align a bunch of wheels, the two side panels and the two ends of the original design when loading.

Day 38

Checked each tender wheel/axle with an ohm meter to be sure that only one wheel conducted electricity to the axle. Checked the wheel spacing with an NMRA standards gauge. Cleaned the wheel treads and axle ends with Brasso using cotton swabs on wood sticks. Scrubbed the wheels/axles and truck frames with dishwashing detergent then rinsed and put them outdoors on a paper towel in the sun to dry and warm up.

Here’s a comparison of the original wheel painting mask and the one I modified yesterday.


Inserted the wheels/axles into the mask. Stuck a blob of removable mounting putty onto each axle end since that is what will make electrical contact with the truck frame.


Also applied the putty to the axle holes and bolster areas of the truck frames then put them onto a holder made of pointed sticks wrapped with masking tape sticky-side out. Sprayed all with a light coat of Floquil Zinc Chromate Primer from a spray can. I don’t know if “primer” in the name really means primer (special formulation that bonds to metal better than regular paint) or if it merely means it’s the same color as zinc chromate primer for simulating models of items such as steel beams. As with all Floquil paints, they are out of production so I’m using up what I’ve got on hand.

After painting, I put the painted items into a self-made dryer that was modified from a food dehydrator. I couldn’t get the original heating element and fan to work at relatively low temperatures so I replaced them with two household light bulb sockets and a computer fan. By choosing different wattages of bulbs and being able to switch on one or both, it’s easy to control. Today’s project uses a 75 and a 40 watt bulb to provide 80 to 90 degrees F during about 70 degrees ambient temperature outdoors.

Day 39

Sprayed the wheels with Floquil Rail Brown on the axles and inner sides of the wheels then with flat black on the outside. Misted some flat black onto the Rail Brown areas and some Rail Brown onto the flat black outer side of the wheels. I’ll leave the trucks in primer until I paint other items.

Day 40
Cleaned and painted the loco pilot and trailing wheels/trucks in a similar manner as the tender trucks. Realized that using primer was probably a moot point because none of the truck frames had been stripped of the factory paint.

Used wooden toothpicks to buff off traces of overspray on the tender wheels.

Day 41
Continued with painting and overspray cleanup on the wheels and trucks from the past few days.

Day 42
Unmasked and buffed off overspray on the loco trucks.

Day 43

Assembled the painted the pilot truck and wheels.

Got serious about locating the electronics in the locomotive and decided that I’ll have to cut off about the top 5mm of the boiler weight. That will be a job to do outdoors with a respirator and safety glasses…but not today.

Started to attach the Current Keeper to the Tsunami TSU-1000 but got stymied by a newby question. I “knew” the answer but thought it odd that it wasn’t addressed in the instructions. Joined the yahoo group for Soundtraxx users and received a quick reply: https://groups.yahoo.com/neo/groups/soundtraxx/conversations/topics/40437 .

Spent modeling time reading up on the RRampmeter. It’s a voltage and amp meter that looks like it would be handy for checking DCC on layouts. http://tonystrains.com/rrampmeter-by-dcc-specialties/ For more info, download the Application Notes (link to the pdf is on the web page).

Day 44

Soldered plugs/sockets to connect the Current Keeper to the Tsunami TSU-1000.

Day 45

“Pickled” the tender frame for 16 hours in white vinegar (5% acidity), rinsed in water, scrubbed it with dishwashing soap, rinsed then gave it a quick scrub with 91% isopropyl alcohol to help drive off the water. In the process I dropped the frame in the sink and the coupler mounting plate broke off at the solder joints. Reattached it with considerably more solder than it had originally.

One of the underside tool boxes came loose (again) so I reattached it with 5-minute epoxy. Scrubbed, rinsed, etc. then sprayed the frame with the same zinc chromate primer that was used on the wheels and trucks.

“Breadboarded” a headlight circuit per the SoundTraxx directions using a pair of IN4001 diodes and one 1.5v micro bulb for a more-or-less constant brightness regardless of voltage. Connected it to a model railroad transformer (not the DCC unit). It worked fine at lower voltages but as I cranked it up the diodes got hot and tripped the transformer’s circuit breaker. Next day: Doh! I failed to include a motor in the circuit — it acts as a “load” to limit the voltage. With a can motor added the circuit works fine.

Day 46

Sprayed the inside of the trailing truck and the underside of the tender frame with rail brown and an overspray of flat black.

Hack-sawed the top 5mm off of the boiler weight then re-installed it. After test-fitting the electronics and the loco frame/motor/gearbox, I found some empty space above the motor so I attached the cut-off part of the boiler weight there with Shoe Goo.

Day 47

No work on the project today unless you count cleaning out old paint from a Floquil bottle that had been soaking in E.L.O. for a couple of weeks. I’ll probably use that bottle to hold the black paint mix (probably Engine Black/Grimy Black/Glaze) for the loco and tender.

Day 48

No work on the project today. I’ve been busy searching and scanning my photos of chalk marks on freight cars for a buddy who is doing a modeling clinic on the subject.

Day 49

No work on the project today. Still working on chalk mark photos.

Day 50

Finished my chalk mark photo search/scans and got back to this project.

Soldered two mud hole covers on the loco superstructure. They had come loose when I was grinding off the backsides of them to gain a fairly smooth surface to glue the weight above the motor on the inside of the shell.

Discovered the remains of where a detail may have been soldered to the underside of the forward running board on the fireman’s side. I didn’t have a clear photo of that area but it appears that one couldn’t see a detail even if it was there above the steam chest. Perhaps it’s just an errant blob of solder.

Laid out and drilled a pair of scupper drain holes on the top of the tender ahead of the rearmost water hatches.

Puzzled over how much detail, if any, to add to the top of the oil bunker. The two Sunset oil hatches are just hatches — missing four clamp-downs and a vent tube. The spout hook and brackets would be delicate to make in scale — I’ll have to add something but not until I get the tender primed and smoothed first. Discovered that one of the holes I had drilled for the handrail stanchions on the bunker is off-center. Partially filled the errant  hole with solder then re-drilled the hole but only succeeded in making an oval hole. Chose the two least-mangled stanchion bases that I had removed from other locations earlier, straightened them some then soldered them in place. Drilled out the solder in the stanchions where the hand rail verticals would be installed at a later time.

Day 51

Washed and rinsed the tender, oil bunker and smokebox door then put them into vinegar to pickle overnight.

Searched online for images and info on cab curtain installations. I have Rio Grande #3552 ones that look good but I’m not sure that I want to take the time to put in the rods that the curtains would slide on.

Day 52

Airbrushed Floquil Primer (light gray) on the tender, oil bunker and smokebox door. Using a newly opened bottle with the red and black label, hardware store lacquer thinned it fine for airbrush use. It went on beautifully. Within about twenty minutes the thinner separated from the paint left in the bottle. Online comments about this suggest that it’s OK for a day or so before it goes bad. After the smokebox door had dried for an hour or so, I planned to airbrush it with a light coat of a silvery color* I had mixed about five years ago for another loco. The paint in the bottle looked OK after stirring, shaking and adding a little lacquer thinner. However, it gummed up the airbrush filter and the brush itself when I tried to spray it. After much cleaning and adding of so much thinner it was nearly water-thin but I was able to mist on enough for a nice color. I disposed of the remaining contents. I’ll try to continue using Floquil (even if it becomes short-lived after adding thinner) for old times sake on this project. Afterward, I’ll responsibly dispose of all of the remainder. At least one bottle dates to the ’70s and many are from the ’80s and ’90s. I have a few bottles of both Scalecoat I and II. It will be easy to switch to that for painting brass. Otherwise, I’ll continue using water-base acrylics for everything else.

*probably Floquil Old Silver darkened with Grimy Black

Day 53


The gray primer has excellent adhesion on the brass. On the smokebox door, the silver metallic flakes in the paint look a little coarse. With weathering, it might look OK or I might respray it with a finer metallic.

Surface defects in the tender and oil bunker were filled with 2-part auto body glaze. It’s a fine-grained polyester filler putty that sets up in minutes. It doesn’t shrink nor expand and can be wetsanded smooth within twenty minutes of application. It’s the easy and permanent way for me to compensate for my metalworking boo-boos.

Day 54

Wetsanded and applied more putty on the tender. Soldered the oil bunker to the tender.

Day 55

Drilled four holes in the back of the cab for a pair of white metal cab curtains by Rio Grande Models, #3552. Only the two vertical curtains will be needed as the 3700-class locos didn’t have a horizontal one.

Day 56

No work on the project today.

Day 57

Fruitlessly looked [again] online for top/front photos/drawings of the prototype tender. I’m following photos of an O scale one. I mistakenly followed the wrong prototype to make one of the water hook brackets (bare brass part on top of the oil bunker) so I’ll need to revise it.


Here’s how it looks after the wet sanding of the auto body putty from a few days ago.

Day 58

No work on the project today but I’ll get back to it tomorrow.

Day 59

Fixed the incorrect water hook bracket and made/soldered on a second one. Bent the handrail for the top of the oil bunker but didn’t attach it — I want to look at it in position for a while to be sure it looks correct. Sanded more of the auto body putty that filled in some gaps.

Day 60

Attempted to solder the handrail to the top of the bunker but ruined it. I’ll have to bend a new one and try again. I did succeed at cleaning out several old paint bottles that had been soaking in acetone for a few days. Assembled the airbrush that had been taken apart for cleaning after the gray primer spraying on Day 52.

Today marks twice the expected completion time but that’s OK. It’s a hobby, not a career.

Day 61


Straightened the top handrail (didn’t need to make a new one as I had previously thought) and soldered it in place. Bent a new curve into the top of each front grab and soldered them in. The engineer-side one still needs a little tweaking. Re-soldered the lower part of each rear grab that had come loose.

Day 62

Located engineer and fireman figures. They will need to be greatly modified to fit into the tiny areas in the cab not filled by the too-large cover/backhead that surrounds the loco’s motor.

Day 63

No work on the project today. After two months of daily postings, many with little activity, I’ll now be posting less often — probably once or twice a week.

Days 64 and 65

Drilled holes in the oil bunker for attaching a step and two toolboxes yet to be made of styrene. Drilling on the back side of the bunker loosened it so I put it back in position and backed up the joints that I could see with 5-minute epoxy on the inside. Brush painted the smokebox door with a thin coat of Polly S Silver to tone down the metallic flakes sprayed on earlier. When dry, I “dirtied” the silver with with a light brushing of dry dark gray pigment (MIG P040 Volcanic Sand).

Days 66 through 69

On the smokebox front, brush painted the headlight and number board Tamiya X-1 Gloss Black. Applied the 3746 number using Microscale 87-64 decals. I spent a long weekend at Yosemite National Park and took this project along — it was done in sight of the famous Yosemite Falls.

Days 70 through 73

Drilled a shallow 1/16″ hole in the back of the MV headlight lens. Wrapped Bare Metal Foil around the sides of the 1.5 volt micro bulb then glued it into the back of the lens with 5-minute epoxy.

Mixed Floquil black paint for the loco/tender in approximately this formula: 6 parts Engine Black, 2 parts Grimy Black, 2 parts Glaze. Brush painted the grab iron on the smoke box front. Painted black over the epoxy and bulb on the backside of the headlight to minimize light leaks.

Airbrushed a light coat of gray primer on the tender.

Days 74 through 79


Installed the headlight lens/bulb/wiring into the smokebox door and added a 2-pin socket.
Made and installed a rear cab light from styrene. This is a tiny lamp on the rear of the roof whose purpose is to illuminate the top of the tender during nighttime servicing.

Days 80 through 85

Tested the Sunset can motor with an RRampMeter using 14 volts DC (not DCC):
0.19 amps (no load)
1.44 amps (stall)

My club may not be able to make DCC work. I now plan to make this loco able to run on DC or DCC.

Cut down the crew figures to fit between the oversized backhead and the cab walls. Engineer (left) and fireman (right) are now skinny because the backhead is oversized to allow room for the electric motor.

Started to make tool boxes for the top of the tender from styrene.

Days 86 through 92

Yikes! It’s been 3 months since starting this one-month project.


Painted the crew figures.

Finished building styrene boxes for the front of the tender. Added a 36″ Detail Associates 6605 grab handle to the side of the box on top (oil heater equipment?). The grab handle might need to be moved downward a bit. Brass rods attached to the tool boxes will aid in alignment when these are attached after painting. The rods will also make it easy to secure them with glue under the tender shell since the tool boxes sit up on “feet” (not yet made) that don’t provide much surface area.

Days 93 through 108


Added feet under the tool boxes. Fixed the grab handle on the top box (oil heater equipment?). Made a rear step from styrene and a rivet decal. I won’t be adding any more detail, such as the water jug and tool box hinges/latches, to the front of the tender as they wouldn’t be seen during train operation. The styrene pieces will be painted separately with Floquil Barrier and then with the same black as the loco and tender bodies for attachment later.

Finally found a fairly good photo of a passenger buffer on the rear of an ATSF tender. Decided that it would be far too much work to scratchbuild the buffer and modify the tender so I’m just going to leave it as is. I wonder how many nit-pickers will notice its absence?

Dead rail (on-board battery power) is starting to look interesting. It seems that I could hook up a receiver that would operate the DCC light and sound functions while running on battery power (instead of power through the tracks). Since this loco and tender will only be for heavyweight passenger trains, I could permanently consist a battery-carrying baggage car behind the tender.

Days 109 through 110

Cleaned up and primered the two cab curtain castings. Made holders for the boiler and other items that needed them for painting. “Pickled” the boiler and part of the frame (suspended so only the steam chests and pilot were in the vinegar) for about 14 hours. It was a mistake to do this for the frame with the drivers still in place. The axle springs rusted and the plated driver tires had stains and corrosion — apparently this was caused by the vinegar fumes. Brushed the worst of the rust off of the springs and polished (but couldn’t completely clean) the driver tires with a 3M Ultrafine foam polishing pad. The pad is the finest grit of five used for polishing paint. Masked the driver tires, rods, etc.

Painted the styrene parts with light coats of Floquil gray primer. I had intended to use up an old bottle of Floquil Barrier but it was so gummy it couldn’t be thinned. Sprayed the inside of the cab flat black to minimize the oversized backhead as much as possible. When dry, inserted file cards cut to size to mask the insides from the exterior black overspray.

Airbrushed the following parts with Floquil (Approx. 6 parts Engine Black, 2 parts Grimy Black, 2 parts Glaze) thinned with lacquer thinner: boiler, frame/drivers, styrene details for the tender, tender shell, sides of the tender frame and the outer sides of the various truck frames. The Glaze added a bit of sheen that looks good but is not quite shiny enough to provide a good surface for decals so I’ll probably shoot some clear gloss onto those areas.

Days 111 through 113


Here are the painted parts on the holders with masking still in place.


Masked and sprayed the lower part of the gearbox and motor flat black.

Days 114 through 117

Removed black paint from the bell and whistle with lacquer thinner using a small paint brush and toothpicks.

Airbrushed thinned Floquil Crystal Cote on the bell, whistle and areas to be decalled. With about 2 parts clear to 1 part lacquer thinner it was too thick to spray. At about 1:1 it went through the airbrush (Badger 150 with the L needle and head) at 30 psi so I used it but it badly orange-peeled on the tender. After drying for a couple of hours I wet sanded it smooth with a 2400 grit pad being careful not to take the paint off the rivets. The loco would have been barely OK but since I was doing the tender, I smoothed the loco areas on the cab and dome where the decals would go. A quick coat of Testors One-Coat Clear from a spray can went on smoothly.

Removed masking on the side rods. I used Formula 560 Canopy Glue, a flexible water-based adhesive, because I didn’t have any Micro Mask, and it worked well. However, it wasn’t necessary. My original plan was to paint the plated parts with flat clear for a metallic look. Instead, I brushed them with Titanium color Model Master Metallizer. When dry, I buffed it with a cotton swab. The Santa Fe paint color for these parts is “Steel” but there seems to be no paint chips available for reference so I’ll rely on a photo of the prototype.

Attached the brake shoes, trailing truck and tender truck frames. Lightly weathered the lower areas of the loco and tender by airbrushing light mists of thinned Polly Scale Dirt while rolling the loco to prevent the rods from casting “shadows” on the wheels. Sprayed similar mist coats of Polly Scale Oily Black.

Began applying decals. Microscale 87-363 decals on the superstructure went on easily. Later I’ll add numbers to the number boards.

The tender numerals in the Microscale 87-64 set are the correct height but are too narrow. The numerals on the Microscale 87-363 set appear to be correct. I discovered this after applying a pair of numbers with Micro Set and Micro Sol. Removing them also peeled off a chunk of clear that required repair.

Days 118 through 120

Removed the trailing truck, installed the wheels and set it aside for later.

Painted the side rods, etc. again with Model Master Titanium and buffed it slightly when dry.

Removed the last of the masking from the loco frame: tire treads, driver suspension and the axle-mounted gear.


Started applying decals to the tender. While letting the Micro Sol wetted decals snuggle down onto the rivets, I knocked it to the floor (wet decal side down, of course) causing the damage circled in red. I had kept the tender shell on my painting holder but laid it down so the side would be horizontal for the Micro Sol to do its work while I went on to other things. I then swiveled my chair and the seat back caught the base of the painting holder sending it all to the floor.

Days 121 through 124

Four months have now passed on this “30 day” project.

Made “hubcaps” punched from .005″ styrene (or sliced from .040″ styrene rod) and .030″ hex styrene then glued them with Alene’s Tacky Glue to cover slotted screws on the rods and valve linkages. Painted Polly Scale Oily Black on rod details and brightened up the rods with Testors Flat Aluminum enamel added to the Metalizer Titanium so they would be a little more visible.


Installed the gearbox/motor and added a drop of Labelle 108 oil to the various bearing points. I couldn’t have hoped for it to run any smoother than it does. I’m breaking it in by operating it on rollers at various speeds in both directions for varying amounts of time. I’ll need to add more flat black paint to the gearbox to make it “disappear” when the boiler is attached.

Scroll down to Feb. 10, 2016 and Oct. 17, 2016 to see revisions to gearbox and torque arm.

Repaired the damaged tender. To my surprise, I was able to straighten the bent handrails to their original shapes. Touched up the damage with paint then applied the decals using plenty of Micro Sol to get them to snuggle down over the rivets.

Days 125 through 129

Sprayed a few light coats of spray can Floquil Flat Finish from on the decalled areas of the boiler/superstructure and tender. When the can started running low I finished up with a light spray of Testors Dullcote on the rear of the tender.

Attached the speaker to the tender floor with Shoe Goo, making sure to get an airtight seal all the way around.

Attached the painted styrene details to the tender shell with 5-minute epoxy.

Brushed on Bob Dively Liquid Masking Film on the numberboards to keep them clean and black for adding decals later. Brush-painted the stack with a mixture of Polly Scale Silver with a small amount of Oily Black to simulate Tarpon Gray. Brush-painted Floquil Gray Primer on the canvas sun shades on the loco to give them the same base color as the cab curtains. Painted the cab curtains and sun shades with a mixture of Polly Scale Reefer White and Mud then weathered with other colors to add grunge.

Days 130 through 142

No activity. I was busy working on a non-railroad model contest entry — and it’s done.

Day 143

As recommended in the Tsunami instructions, I made drawings of the electrical systems for loco and tender. It was a little complicated because I’m setting it up to run via DC (with diode-drop constant brightness headlight) and also DCC. By plugging/unplugging various items I will be able to switch between the two. I don’t have an easy way to test DCC so it will be a while before I’ll know if that part of it works. Months ago, I had intended to “breadboard” it before installation to test it but didn’t.

Days 144 through 149

Made revisions to the wiring diagram, made the DC wiring and installed it. The loco runs fine by itself but won’t when the tender is attached. The tender doesn’t seem to have any shorting problems. All of the tender’s fireman’s side wheels pass the negative rail’s current to the hitch pin (and all of the engineer’s side wheels do not). The loco runs fine by itself when the negative connection from the transformer is attached to the drawbar (and the positive goes through the engineer’s side rail), even when the tender is sitting on the same track.


Each rectangle is a plug/socket. The two pairs of diodes are a constant voltage circuit to power the headlight.

Day 150

150 divided by 30 = 5 months! I’m still making rookie mistakes but at least I’m resolving them on my own. Thinking that yesterday’s electrical problem might be caused by intermittant contact I added a wire wrapped around the middle axle of each tender truck and soldered it to top of the truck. The wires were then connected to the hitch pin via a terminal block. That “belt and suspenders” design doubly ensures contact but it didn’t solve the problem. It may prove useful later when running on DCC although the Circuit Keeper connected to the Tsunami board will achieve the same end.


Turning to the loco, I checked for continuity and discovered that I had installed the pilot truck 180 degrees off. The loco worked fine before because it was getting positive power from the right-side rail (engineer’s side) and negative only from the wire clipped to the drawbar — the fact that positive power was bridging over to the left-side rail didn’t affect the loco (nor the tender also on the same track) at all.

With the pilot wheels turned around, the loco WITH tender are running fine with power coming only from the rails. On the Bachrus roller stand there are only two minor problems evident: slight fore-and-aft rocking probably due to something out-of-round; and a little bit of noise from the original gears and gearbox. Now it’s time to continue with the light weathering and add the remaining cosmetic details. That’s the part of model building I like best.

Days 151 through 158



It’s done! Well, at least, it’s as done as it’s going to be for awhile. I could add some soot weathering on the top surfaces. I left off glazing the windows and adding cords for the whistle and bell — it’s not a contest-quality model, it’s for running at public shows. It should be making its debut at The Big Train Show in Ontario, CA on June 6 and 7, 2015 on the ’20s & ’30s Modular Model Railroad layout. For club and show details, see http://trainweb.org/20s30s/events.html .

See a 25 second video of it running on rollers here: https://vimeo.com/128074982 . Disregard the odd coloring of the model in the video — I tried to compensate for auto-exposure and auto-white-balance. It looks better than it did right out of the camera (but not much).

February 10, 2016

Upon completing it, the loco just wouldn’t run right. Intermittant electrical shorts seemed impossible to find even as I attempted to over-insulate everything I could find…and even insulate things that shouldn’t have needed it. Also, it was OK when running on rollers at home but it sounded like a coffee grinder on the layout.


While replacing the original SMS gearbox with an NWSL 139-6* I discovered that the insulated driver on that axle was shorting between the wheel and tire. I carefully removed the tire and slopped it up with black Floquil paint. After letting it dry for a few minutes to get gummy, I pressed the tire back onto the wheel.

Those two changes made it run like a champ on our 45′ x 27′ modular layout at a Great Train Show a few weeks ago.

*actually, I couldn’t find a 139-6 to buy by itself but I did discover that it was one of the two gearboxes in the NWSL 148-6 set intended for articulated locos.

Oct. 17, 2016

Pulling more than six cars (one brass, five plastic) for several hours caused trouble. The gearbox rotated forward, putting side pressure on the main gear shaft that caused the front bushing to overheat.


The reason was that the torque arm was too flexible and allowed the gearbox to rotate. Fred Hill, The Original Whistle Stop, Pasadena, CA analyzed the problem based on my description. Thanks, Fred! I had presumed that the problem was that the loco was pulling too much weight so I was expecting to have to add power trucks to the tender or baggage-express car. I’m glad that I was wrong.


With the motor and gearbox in the correct locations I cut and bent a piece of brass square tube to strengthen the torque arm. I removed the old torque arm and soldered the stiffener on. Instead of Shoe Goo I used 5-minute epoxy to cement the arm onto the motor and gearbox. Next, I’ll need to replace the “hubcaps” that cover the screw heads on the main drivers and touch up the paint chips on visible parts of the loco.


The engine has been running fine on rollers for about a half-hour. The real test will come when it pulls nine or ten cars (probably three brass and the rest plastic) for an hour or two.

June 5, 2017

On a large module layout the engine pulled about five cars for a few hours without trouble. However, performance then quickly deteriorated with the problem appearing to be poor gear mesh inside the gearbox.


When the gearbox rotated forward, prior to my Oct. 2016 improvement of the torque arm, the misalignment of the worm shaft heated up the bearings and distorted the plastic gear case holding everything together. I have now replaced the gearbox with a similar NWSL one. It runs great with no load on the Bachrus rollers so I’ll reassemble the rest of the loco and we’ll see how it does in operation.

February 23, 2019

The loco only runs a couple of times a year at public shows. As before, it’s OK for about two hours before the front gearbox bushing overheats. That melts the gearbox plastic and the bushing/shaft move forward and eventually the U-joint pops out.


So, I did some “hillbilly engineering” in an attempt to cure the symptom. I don’t know what the cause of the excessive stress/temperature on the front bushing is. To forestall future problems I’ll limit running to about 1-1/2 hours followed by several hours of rest to cool down.



12 responses to “Locomotive and tender

  1. Bob Battles

    Greetings! I own an engine similar to yours so it was nice to see what you did to the oil bunker! Mine is a Sunset but has the correct-size drivers, & the oil bunker is very much like yours after you did the modification. As for the motor being totally isolated, as long as it has two terminals on it like yours does, there’s nothing to be gained by isolating it from the frame– that rule only applies to open-frame motors. Your idea of the thin strip of plastic on the bottom of the pilot is a good one; Scotch tape held on with a couple drops of ACC works OK too. I wrote an article in the Dec. 2013 MODEL RAILROAD HOBBYIST mag on installing a Tsunami sound decoder in a brass loco so maybe it would be of some help. You’re doing a nice job so far! Bob Battles

  2. charley2030

    Thanks, Bob. Could you post a link to photos of the front of your tender? You’re right about the can motor not needing to be electrically isolated — it was just an easy “belt and suspenders” thing to do as I’m a newby at this. I recommended your MRH article in my Day 26 post above.

  3. Pingback: Still pluggin’ along | steamblog

  4. Keep it up! You will get there eventually.

    Being in the middle of similar challenges – intermittent shorts and running less sweetly than desired, while already “finished” is a tough position.

    I feel your pain!


  5. charley2030

    Thanks, Rene. For DC running, it’s finished. If and when my module club gets the DCC operating then I’ll work on installing the Tsunami and getting it to work. I planned ahead for that by installing plugs and sockets in strategic locations in the loco and by installing the speaker and wiring in the tender.

  6. Logan H Thurman

    Okay, I have to say, That’s one great job so far, Infact If you can maybe help me on my Steam Custom build project later down the road.

  7. Tim Logan

    Well Done! I like your repower work and tender modifications. I’m also glad Fred who is a personal friend of mine could assist you, prince of a guy. I have 6 of these which will become various Coast Lines and Valley Division versions about 1949-1952. I suspect your aware the large letters Santa Fe was placed on 15K tenders from the mid 40’s till retirement. I am also a maintainer on 3751 and if you plan that project, I can probably help with data or pictures. Here’s an image of the 3746 at El Paso later in it’s career. https://s-media-cache-ak0.pinimg.com/originals/c3/07/aa/c307aacc5889df7cec42953e9d423290.jpg
    Tim Logan

    • charley2030

      Thanks for responding It’s great to hear from someone who is actively participating in both models and the real thing. The large SANTA FE lettering on the tenders is an easy spotting feature for me: if it’s there then it’s too “new” for me.

    • charley2030

      Cool! Thanks. The link is for an ebay auction so it may only be viewable for the next few months.

      • Tim Logan

        I personally prefer just the numbers only, so fortunately most the engines of this class I am modeling have the 12k tenders which did not get the large lettering. A few had a back up headlight on the tender, plus tunnel bonnets, disk main drivers and a few with forward centered bell and extended cab.

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