Category Archives: Skookum

Baldwin Unitah NG 2-6-6-2T

Two of the few US narrow gauge Mallets were Unitah 50 and 51.

Unitah Mallet Proto 1

This is a side tank saddle tanker that served a mining road and later a couple of timber roads.  With the exception of the fact the Roundhouse 2-8-0 and 3 in 1 kits are outside frame locomotives they match up fairly well.  I printed and did takeoffs from a Jon Davis drawing.

Unitah Mallet Davis Drawing

My ruling dimension for takeoffs is driver diameter which was known to be 42″ on the prototype.  What follows is a takeoff table comparing HO dimensions converted from the drawing to actual dimensions from the model.

Unitah Takeoffs

Note that overall length is almost identical as is the wheelbase between drivers in driver blocks.  Driver diameter is a bit smaller on the model which will give it more of a hunkered down look.  The wheelbase on the model is quite a bit longer but is adjustable due to bashing.  The model makes up for the longer block to block wheelbase with a shorter front deck.  As the wheelbase in the model is adjusted, room will be gained for a longer deck.  Heights are close.  The cab is longer on the model but needs to be bashed to add a door and bunker.

Distance from the rearmost driver to the rear truck and frontmost driver to the front truck are adjustable.  The side tanks need to be scratch built so can be adjusted to fit the space.  Overall, the model is close enough to the prototype for my purposes.

Here are some more prototype photos and in one case a LGB Unitah photo for details.

Unitah Mallet Proto 2

Unitah Mallet Proto 3

Unitah Mallet Proto 4

Unitah Mallet Proto 5

Unitah Mallet Proto 6

I will keep a builders log as I proceed with this project.

Baldwin 0-4-2T Switcher

A number of related posts show a 2-8-0 Consolidation, a 2-8-2 Mikado, a 2-4-4-2T  Logging Mallet, a 2-6-6-2T, and a 0-6-0 Switcher being built by bashing Roundhouse 2-8-0 Consolidation and 3 in 1 kits.  With this much slashing and bashing, there are going to be parts left over.  So why not use them to bash something.  A 0-4-2T switcher immediately comes to mind.  So here is a Baldwin prototype.


Here are its specifications.



So lets start scrounging for parts.  In building the 2-6-6-2T Mallet, two kits were used – an outside frame 2-8-0 and a 3 in 1 kit.  The two frames were cut as follows.  The right side of this cut went into the 2-6-6-2T Mallet.  What if we used the left side for the Porter frame along with …





2-6-6-2T Frame 1

The part cut off from the second frame.  The left portion was used in the 2-6-6-2T.  the right portion of the second frame could be joined with the left portion of the first frame to create a frame for the 0-4-2T.

2-6-6-2T Frame 2

The boiler-tank-cab-bunker from the 3 in 1 kit was use in building the Mallet.  that’s the top portion of the next image.  The boiler and cab from the 2-8-0 were surplus (bottom portion).


Of course, the boiler would need to be shortened (chop – chop) and a bunker placed on the back of the cab.  And a saddle tank would need to be constructed.  A set of cylinders was surplus from the bash along with a set of piston rods and associated gear.  Side rods would need to be fabricated,  Of course this is an outside frame loco – a bit of a stretch.  “But boss, the parts were just laying around …”  The North Pacific Coast had a machine shop and the expertise to do this.

It would be a fair amount of work, but there would be no parts to buy – except for the motor, gearbox, sound board, and detail parts.  The whole engine could be done for $175.  Let’s park this project and see what happens.



0-6-0 Porter Switcher

Now that I have the concept of a 2-6-6-2 down, what else could I do with the Roundhouse kits?  How about one of my real needs, a 0-6-0 switcher?  Here’s a Porter saddle tanker prototype.  No 65 is a working engine, toiling for the WK&S in Kempton, PA.  Photos by Jeff Z are used with Jeff’s permission.

0-6-0 Porter Saddle Tanker

Another photo of her current state shows off her switching pilot, air compressor, and headlight.

0-6-0 Porter Saddle Tanker 2

A third shows off the domes, bell, tank hatch and the generator.

0-6-0 Porter Saddle Tanker 3

Here is her builder’s photo.

0-6-0 Porter Saddle Tanker 4

OK, she’s very cool.  And Jeff is an excellent photographer.  But how do I build her in HOn3?  First of all, I wouldn’t be going for an exact rivet by rivet replica.  An engine with the same look and feel would do for my purposes.  Call it a freelance engine based on a prototype.

I could use the boiler-tank-cab-bunker shell from a Roundhouse 3 in 1 kit.  I’d need to shorten the tank a bit, reducing the distance between the two domes closest to the cab.  Some bashing of the cab would be necessary including removing the rear portion of the top and cutting off the lower portion of the front of the cab.  The 3-1 kit part is the upper portion of this photo.  The way Roundhouse designed this shell, it makes the door height look out of scale.  I might also remove the door and show an additional step inside the cab.  I’d live with the vertical bunker instead of the slanted version on the prototype. As this is the Sausalito switcher, I’d convert to oil as oil tanks are near by on the docks.  In the following photo, cuts are the area inside the red rectangles.  After doing the first boiler cut between the domes, I’d evaluate whether I need to do the second.

0-6-0 Porter Upper End

Then I would need to do some surgery on the frame.  The surgery involves three cuts, two taking out the front set of driver bearings and the third taking off the road pilot.  Because the drivers are powered at the second set, the mechanism for powering the locomotive won’t change.  The front pilot would be replaced with a switching pilot like on the prototype shown so nicely in the second photo.

0-6-0 Porter Frame

Am I troubled by the fact I’m using an outside frame kit to model an inside frame locomotive?  Not really.  This is a freelance engine based on a prototype.  And the rotating counterweights on the model will add visual interest.

I’ll need to shorten the side rods.  If I’m careful with my cuts, I may not need to modify the piston rods and associated gear much at all.  Another engine parked at the concept stage waiting for parts.

Of course, I could also consider a 0-4-0T or 0-4-2T Porter switcher.  Same concept, different cuts.  So many engines to model, so little time.


Baldwin 2-6-6-2T Logging Mallet

The project is based on this locomotive, a 2-6-6-2T  Logging Mallet that once ran for the Clover Valley Lumber Company. This locomotive doesn’t exist in HOn3 space.


Then I came across this eBay listing.

Roundhouse 0-8-0

This is an old Roundhouse kit that allows the construction of a static (non-powered) steam engine.  The photo shows an 0-8-0T.  But this kit was designed for kit bashers – like me.  The kit offers another option, a 2-4-4-0T articulated shown in the bottom of the following photo.  This engine would never have existed in the real world.  But it sure fired my imagination!

2-4-4-0T Option

If you look at the parts set, it includes the components to model the above 2-4-4-0T.  If you look more closely, the frame and running components are the same as those in the Outside Frame Roundhouse 2-8-0 Consolidation kit with the exception of the connecting rods and piston rods.  But as you can see, these parts are in the kit.  If you compare the two kits in the following photos, the locomotive frame is the same as are the counterweights and under frame.  There are two sets of pistons in the bag as well as the drivers.  There are two sets of piston rods.


I happen to have two of the 2-8-0 kits. Those two kits are powered.  I also have quite a few brass detailed parts, an extra set of drivers and extra front and rear two wheel trucks that are part of the extended parts set in one of the two kits shown in the following image.  The parts set has a set of drivers in the upper left corner, a set of tender trucks, and front and rear pilots.  There is a second set of tender trucks under the tender.  There is also another complete set of drivers in the box on the right side.  There is a fairly complete set of brass detail parts.  Not shown is two brass domes (one sand and one steam) a brass air compressor, and a brass pilot I picked up in separate auctions.

2-8-0 bund

I know how to make these kits run smoothly.  The drive train parts are available from North West Short Line – gearbox, axle gear, and can motor.  You can see that the 2-8-0 parts set already has upgraded NWSL gears.  Did I mention that all three are HOn3 kits?

The 2-4-4-2T would be created by cutting the frame for a 2-8-0 Consolidation in half and inserting an additional pair of cylinders from the 3 in 1 kit.  The boiler-tank-cab-bunker from the 3 in 1 kit is almost perfect in size for this locomotive.

Logging Mallet Frame 3

The next logical step might be to use a Roundhouse 2-8-0 Outside Frame kit and a 3 in 1 kit to produce a 2-6-6-2T like the Clover Valley Mallet.  The first frame would be cut into a 2-6 block by removing the last driver pair and the remainder of the rear frame.

2-6-6-2T Frame 1

The second frame would be cut into the 6-2T block by removing the front driver pair and the rest of the front part of the frame.  The second set of cylinders would go between the two driver blocks.

2-6-6-2T Frame 2

The boiler would need to be extended to deal with the longer frame.  The boiler diameter is from the 3 in 1 kit is 3/4″.  Plastruct makes a tube in that diameter with 1/16″ walls.  Or the size of the boiler could be upgraded to 7/8″ or 1″.

2-6-6-2 Boiler ExtSide rods could be cut down to handle a six coupled driver set rather than the eight coupled sets in both kits.  Cylinder mounting would be similar to the 2-4-4-2T including piston rods, yokes, etc.

Note that this is an outside frame locomotive and the Baldwin Mallets were all inside frame engines.  But virtually all of them are standard gauge locomotives with 4′ 8″ between the rails.  Had Baldwin been asked to produce a logging Mallet for 3′ 0″ narrow gauge, they may well have recommended an outside frame.  An inside frame locomotive would be a bit tippy on curves if armed with a large boiler.  Given this is a freelance locomotive and the parts are outside frame parts hopefully the rivet counters will forgive me for deviating from the norm.

Of course there is the difference in the cylinder sizes to deal with.  Or is there?  I was poking around on Jon Davis’s web site, Mallets in the Tall Timber and came across his discussion of simple Mallet Type Articulateds like  Weyerhaeuser 111 with both sets of Cylinders the same size.  Note the double stack.


At his site Jon has a very useful discussion of the advantages of simple versus compound Mallets including this drawing of the steam routing on a Simple Mallet Type Articulated.

Simple Mallet Articulateds

Check out his discussion on this page and let Jon fill you in on the details.

Powering this unit would be less of a challenge than with the 2-4-4-2T as there would be plenty of room to mount two motors.  The 2-8-0 Consolidation powers the second driver pair from the front,  That driver pair exists on both driver blocks.

Given that this is an easier bash than the 2-4-4-2T, I think I will take it on first.  A builders log will be maintained.  Individual posts for that blog will be shown below.

Skookum Drawing Takeoffs

The objective of this page is to determine whether a visually convincing model of the Skookum, a Baldwin 2-4-4-2, can be assembled using Roundhouse parts from their inside frame 2-8-0 Consolidation and their 3 in 1 kit aimed at producing either a x-8-0T or a X-4-4-0T in HOn3.

Noting the proposed service is important.  This engine will pull lumber consists out of Duncan Mills.  A 2-4-4-2 is desirable because of its combination of tractive power and the ability to navigate relatively tight curves.

HOn3 is already a deviation from the prototype which was a standard gauge engine.  I would expect had Baldwin produced a 3′ narrow gauge version of the Skookum, it would have been lower and shorter as was typical of narrow gauge engines in relation to standard gauge.

Here is a set of Skookum drawings.


Dimensions are visible.  I blew this drawing up to fill an 8 1/2 by 11 piece of paper.  Coincidentally, the drawing is close to HO as you will see from the takeoffs.

Skookum Takeoffs

My ruling dimension from the drawing is the wheelbase of the rear pair of drivers which is 66″ from the drawing.  I took off length using my digital caliper and it turned out to be 0.779″ on the drawing.  Dividing the 66″ wheelbase by 87 (HO) translated to a 0.759″ wheelbase at scale.  The actual wheelbase measured on the Roundhouse frame is 0.52″ which translates into 45.24″ at 1:1 scale.

So the separation between the drivers on the frame (45.24″) is undersized in relation to the prototype (66″).  I would expect the narrow gauge locomotive to be shorter.  But the rear drivers wheelbase in the models frame is only 68.5% of what would be expected from the prototype drawings.  Of course this wheelbase could be changed with quite a bit of hacking of frame, side rods, cylinder rods and other components.  I’m going to park that problem for now.

Overall wheelbase including tender is 662 1:1 scale inches which translates to 7.609″ in HO scale.  That is about the same as the 2-8-2 Blackstone Mikado.

Driver diameter is 46″ on the prototype which translates to 0.545″ at HO scale.  The drivers on the Roundhouse models are 0.443″ which translates to 38.5″ at 1:1 scale.  Changing the model’s driver diameter would be a major issue on the Roundhouse kits.  The kit drivers are 83% of the diameter of the prototype.  With smaller drivers, you would expect to see closer spacing (wheelbase).   Other dimensions are not far out of line.

The next photo compares the drive train of the Roundhouse 2-8-0 to the drawing of the Skookum’s drive train.  Given that the drawing is close to HO scale, the drivers and the driver spacing is small in relation to the prototype.  Of course we are looking at the Roundhouse Outside Frame.  The Roundhouse Inside Frame  anything would look even smaller although it would be the same length.


Does this kill the concept of using the Roundhouse kits to build a 2-4-4-2?  No, but it will need to be a freelance locomotive.  Calling it the Skookum would draw hordes of deceased rivet counters out of their graves like zombies, all headed in my direction.  Visualize that scene for a second.  It runs chills up my spine.

The next photo shows the Roundhouse Boiler in relation to the Skookum boiler.  It is a bit shorter but given the fact the freelance 2-4-4-2 will have a shorter wheelbase, it will work.


Getting the boiler out brought another issue to my attention.  The following shot compares the Roundhouse 2-8-0 boiler and cab to the boiler/saddle tank/cab from the 3 in 1 kit.


Yikes!  What should be my smallest locomotive, the 0-8-0T, would be the tallest and possibly the biggest.  What was Roundhouse thinking?  I’m going to have to give the solution to this dilemma some thought.  I could use the 3-1 kit parts for bashes with other Roundhouse kits.  I could fabricate (scratch build) a shell for a 0-8-0T.  But it turns that locomotive not a much bigger project than I anticipated.

Another alternative might be to build a 2-4-4-2T Logging Mallet.  Something along the lines of this Booth Kelley Mallet, except as a 2-4-4-2T rather than a 2-6-6-2T.  Such an engine should have a chunky look.  The outside frame with its counterweights would give that feel.  And the cab/bunker looks a lot like the cab/bunker in the 3 in 1 kit.  Hmm.  But the tank is different.



How about this 2-6-6-2T logging Mallet?


The boiler is a bit longer than the boiler in the 3-1 kit.  But there would be only four driver wheels rather than six.

Roundhouse Kit Detail Parts

If I want these engines to be a family, they should have a similar look.  That gets down to paint and lettering.  But it also applies to detail parts.  Here are the detail parts selected for all four engines.

All will have the same stack with the following spark arrestor.  I’ll pick the stack once the spark arrestor arrives.

Spark Arrestor

All will be oil fueled.  An appropriate oil bunker will be added to the tender and to the bunker on x-8-xT engines.  A hatch will be located for oil and another for water.  Here is the water hatch.  The water hatch will be on the tender for engines with tenders and on the bunker for the x-8-xT locomotives.

Water Hatch

This will serve as the oil hatch.

Oil Hatch

All will have the same headlight, mounted on the boiler.  Attempts will be made to electrify the headlights with LEDs,


All will also have tail lights on the rear of the tender for this with tenders and on the back of the bunker for x-8-xT locos.  These will also be electrified.

Tail Light

In some cases, headlights will be mounted on the pilot.

Pilot Mounted Headlight

All will have generators mounted on the top of the boiler.


All will have air compressors mounted on the side of the boiler,

Air Compressor

All will have air tanks mounted below steps on the boiler.  Lines will need to be run from the compressor to the air tank, and from the tank to appropriate places on the locomotive sand tender.

Air Tanks

All will have cylinder lubricators mounted on top of the cylinders.

Cylinder Lubricators

All will have a brake cylinder mounted in a visible area below the tender.  Lines will need to be run to the brake cylinder.

Tend Brake Cylinder

All will have air whistles mounted on the side of the steam dome.

Air Whistle

All will have air ringer bells mounted on top of the boiler.

Ringer Bell

Here is the Pilot Beam for yard switchers.

Pilot Beam

Note: Other detail parts will be added as the project evolves including piping, back head details, tender details, etc.

Backhead Parts – Diagram shows back head for NPC No 21

The problem with back head parts is often, nobody sees them.  But I’m going to list them and show examples.  The following diagram was a collaboration between David Fletcher, Keith Christensen, and yours truly on what the back head might have looked like for North Pacific Coast No 21, my Holy Grail locomotive.  Keith has since passed away and owned the last remaining Class A Climax.  NPC No 21 was unique in that it was the first railroad engine with a marine boiler, and the first cab forward locomotive.  It was also arguably the first locomotive designed from the beginning to be oil fired.  What I’m saying is this back head illustrates parts placement for a very unusual locomotive.


Parts shown on the drawing (along with a few others) are:

  • Throttle
    Backhead Throttle
  • Johnson Bar
  • Gauge Cluster
    Gauge Clusters
  • Brake Stand
    Air Brake Stand
  • Oil Firebox door
    Oil Firebox door
  • Lube Tray
  • Hydrostatic Lubricator – Oil
    Hydrostatic Lubricator
  • Calledan Injector – Water
    Injector with PipingSteam Locomotive Injector
  • Sight Glass
    Dual Sight Glass
  • Tri-Cocks
  • Drip Funnel – Tri-cocks output through the floor
    Drain Funnels
  • Engineer/Fireman Seats
    Engineer-Fireman Seats
  • Auxiliary water pump – Water or oil
    Feedwater Pump
  • Feedwater Heater
    Feedwater Heater
  • Turret – distributes steam to various devices
    Turret Valve

Mallet Specific Parts

  • Pilot Mount Headlight
    Pilot Mount Headlight
  • Unitah Lead Truck
    Unitah Lead Truck
  • Pilot Deck
    Pilot Deck
  • Double Stack
    Double Stack

X-8-X Kit Construction – Frame and Drive Line

In viewing these images, keep in mind this is a merger of three separate kits:

  • A Roundhouse HOn3 Outside Frame 2-8-0 Consolidation
  • A Roundhouse HOn3 Outside Frame 2-8-0 Consolidation with an extended parts set.
  • A Roundhouse HOn3 3 in 1 kit designed to produce a static 0-8-0T or 2-8-0T or 0-4-4-0T or a 2-4-4-0T

This Image shows the engine frames from these three kits as well as the under frame that suppers the drivers.  Note that there are three frames as you would expect.  There are four under frames, two of which came from the 3 in 1 kit.  Why two under frames from the 3 in 1 kit? Beats me.  These parts have been separated from sprues and the flash cleaned up using the tools on the outside of the photo.  I can’t tell which part came from which kit any more.  It doesn’t matter as they are identical.  The fact the parts are identical makes a strong statement that it would be relatively easy to power the static kit in a 0-8-0T or 2-8-0T configuration.

Kits White Metal 1


These are the cylinders and yokes from the combined kits.  Note that there are four and they are identical.  Two of the four are from the 3 in 1 kit, allowing a modeler to bash a static 0-4-4-0T or a 2-4-4-0T.  If I use this 3 in 1 kit parts to produce an operating 2-8-0T, which I intend to do, one of these parts will be freed up for the 2-4-4-2 project.  The flash on these parts is typical of what comes out of one of these kits.

Kits White Metal 2

In this photo, a little quick work with two files, took care of the flash.  The scratch marks will be covered with paint.

Kits white Metal 3

This next photo shows the drive line components from the combination of these three kits.

Kits white Metal 4

I’ll deal with what’s here by part starting in the lower left corner and going counterclockwise.

  • Side Rods – There are six here and the only brass part in this image.  One of the six is attached to the piston rod.  This is a sufficient number to fabricate three x-8-x drive trains.  If two of these rods are cut in half, the pieces could be used on a 2-4-4-2.
  • Piston Rods – There are eight here, two more than needed to construct three x-8-0 drive trains.  The extra two could be used in constructing a 2-4-4-2.
  • Counterweights Short Pin.  The pins are the attachment point to the side rods other than where the piston rod connects.  There are 24.  Only 18 would be needed for three x-8-x drive trains.
  • Counterweights Long Pin.  The long pins connect to both the side rods and piston rods.  There are seven.  Six are needed to construct three x-8-x drive trains.  Eight would be needed if one to the three engines built was a x-4-4-x.  So one would need to be either borrowed from annotate kilt or fabricated.
  • Pilot Bearings – Are used to support a leading or trailing truck.  There are four.  So some combination of up to four leading and trailing trucks could be supported.  It should be noted that the second 2-8-0 Outside Frame Consolidation kit has an extra brass lead truck and trailing truck.
  • Pilot Bearing Caps – there are three.  If all four pilot bearings are to be used, an additional pilot bearing cap would need to be fabricated,
  • Yokes – support the back end of the valve guides.  Three are in the set.  four would be needed if one of the three engines is to be a x-4-4-x.
  • Valve guides – There are eight.  Six are needed for three x-8-x engines.  Eight would be needed if one is a x-4-4-x.

In summary, so far we are short a long pin counterweight, and a yoke if one of the engines coming out of this set is a x-4-4-x.  The yoke could be fabricated from styrene and brass rod using a white metal yoke as the pattern  The counterweight could be fabricated using one of the extra short rod counterweights.  Drill out the short rod and replace it with a longer brass rod.

Flash was removed from these parts and they are ready for use.

I hacked one of these frames to ready them for a 2-4-4-2T logging Mallet.  You can see the cut line between the second and third spring.

Loggging Mallet Frame 1


This would be the configuration with a second set of pistons.

Logging Mallet Frame 2

This shows the frame and pistons in relation to the boiler-tank-cab-bunker.

Logging Mallet Frame 3

The next step in this process is to figure out how to power it.


2-4-4-2 Skookum Class Ideas

Here are some images related to the Skookum page.  This is a scrapbook of photos on various topics along with my reaction.

Powered Drive Line

Roundhouse 2-4-4-0T Bash 1

This is a 3-1 kit bash by Bob Boudreau.  It shows his approach to articulation of a 2-4-4-0 saddle tanker.  Note that his front truck pivots under the boiler shell and is unattached to the rear truck unit.  I love his detailing.  Here is how he approached the rear truck unit that involved attaching the rear cylinder to the rear four set of derive wheels.  This is an outside frame set but a similar concept could be used with the inside frame set.

Roundhouse 2-4-4-0T Bash 2

This shows the front and rear drive components.  Of course Bob’s model was static.  He didn’t need to deal with powering the locomotive.  The challenge in the Roundhouse kit is the motor normally mounts in the rear of the locomotive boiler.  But power is delivered to the second driver pair in the front unit.  That delivery is complicated by the fact the cylinder yoke for the second pair of cylinders is mounted in between.

Roundhouse 2-4-4-0T Bash 3

One option is to install two small can motors (NWSL 1220S), each powering a driver block.  Given I’m building a logging Mallet and using the boiler-tank-cab-bunker unit that came with the 3 in 1 kit, There may be sufficient room for two motors, even allowing the front driver block to pivot as the tanker shell extends almost to the front cylinders.

Logging Mallet Frame 3

Another option would be to take the approach in this drawing from the NWSL web site.  I have the middle unit on order as well as both motors commonly used with these locomotives.  the angled approach may be able to go over the middle set of cylinders.

NWSL Articulated Gearbox

Once the middle set of parts (0.3 Mod idler gear) and I have both sizes of motors, I’ll take the approach that makes the most sense.