North Pacific Coast No 21 – 3′ Narrow Gauge

Prototype Research


This was the most innovative engine ever built by William (Bill) Thomas, the NPC master mechanic who was nationally known and holder of a number of patents.  This engine was constructed with parts from No 5, the Bodega.  The Bodega was a Baldwin 4-4-0 purchased by the NPC in 1875 as a 3′ narrow gauge engine.  It was wrecked and scrapped around 1897.

Thomas used the running gear and frame from No 5 to build No 21.  But he added a new boiler and cab, installed in reverse order creating a locomotive that was unique and first of its kind in a number of important areas.  According to Harlan, Thomas received a patent on this locomotive design.  What is not clear is which of its many unique features were the subject of the patent application.  The Southern Pacific claimed that their adaptation of the cab forward design was not a patent infringement as all they did was take an existing locomotive and turned it around.  Neverless, this locomotive had a number of features that set it apart from any locomotive built before 1900.

  1. It was the first cab forward locomotive and as such lays claim to being the grandfather of the Southern Pacific’s cab forward articulated locomotives.
  2. It used an oil burner for firing the boiler.  Some claim it was the first oil fired locomotive although others claim other railroads experimented with oil firing prior to 1901.  It was certainly the first locomotive designed from the ground up to be fired with oil.
  3. The boiler was a marine boiler, the first to be installed on a locomotive.  Jim McAdam, the line’s master boilermaker constructed a marine water tube boiler, slanted toward the rear of the engine for good circulation.  Water was heated through sixty three-inch tubes through a corrugated furnace inside the boiler shell.
  4. A steam tube mounted to the top of the engine replaced the steam dome on conventional engines.  The sand box was mounted beneath the boiler.
  5. The tender was a flat car with vertical tanks for oil and water.

No wonder No 21 was referred to as “The Freak” as it moved up and down the line.  One author says, “When the oil jets were opened, the fire boomed and roared like a blast furnace.  Flames flared from open seams in the fire box.  When No 21 passed at night, its fire lighted the countryside.  Windows in houses a half a mile distant shook and rattled when the locomotive rolled by.”

The 3 following drawings are from George Harlan’s “Those Amazing Cab Forwards” published in 1983.

21_DRwg_Boiler Side_4x2

This is a side view showing boiler detail.  Click photo for a larger image.


This is a front and rear view.  Front view shows boiler piping.  Click photo for a larger image.


This is an exterior side view drawing.  Click photo for a larger image.


This is a front and rear exterior drawing.  Click photo for a larger image.

This series of photos, also from the Harlan book shows the boiler under construction.


This is the interior portion of the boiler containing burner and tubes.  The inner boiler is being slid into the outer boiler.  Click photo for a larger image.


This photo shows the exterior boiler jacket.  As the above photo shows the area between the interior and exterior portion contained water.  Click photo for a larger image.


This is a second construction photo.  A portion of the boiler shows inside the cab.  Note: This photo is reversed.  This is the fireman’s side.  Click photo for a larger image.


This photo was taken during the construction process.  The boiler is well back in the cab interior.  Click photo for a larger image.

The following is a fairly complete set of in service photos.


This photo shows No 21 on her trial run with Bill Thomas at the throttle and Bill Wosser firing.  Note the headlight placement.  Click photo for a larger image.

21_Pass Serv_4x2

This in service photo is the best side shot of controls.  Click photo for a larger image.


This in service photo shows No 21 at Point Reyes.  Click photo for a larger image.


This photo shows No 21 in service on Christmas day in Occidental in 1901.  Click photo for a larger image.


This final shot shows No 21 crossing a trestle in San Anselmo in 1902.  Note that the headlight has been raised and large tube has been added to supply additional air to the oil burner firing the boiler.Click photo for a larger image.

Alas, No 21 suffered from a lack of weight over the drive wheels causing it to be more prone to slippage than the other NPC 4-4-0s.  In addition, it was hard to find crew with the expertise to fire this unusual stem engine.  Crews were nervous because of the lack of protection in the event of an accident.  Apparently seats at the rear of the cab needed to be raised to allow the crew to exit to the running boards.

According to Harlan, she was not retired as a result of a fireman mistake as pointed out in a number of other publications.  Rather the burners were too close to the steam generating tubes, causing them to blister.  This was invisible to those servicing the engine.  She was doomed from the beginning.  But she was also the father of the Southern Pacific Cab Forwards.  The following posts provide additional detail on this innovative engine as well as some examples of models built from this prototype.

Modeling NPC No 21

My first model of NPC No 21 is a HOn3 parts kit from Wiseman Model Services.  They sell a parts kit that can be used to model a static display.  You will see a discussion of that construction in the list that follows.  I’ll probably use it as a very interesting flat car load or park it on a siding at the PC&N engine terminal.  While it was originally intended for a running model, it never reached that point as the original designers were unable to get it fully operational in testing.

But I really want a running version.  So in addition to being used to model a static engine, I’m also considering it to be an exploded parts diagram and a set of 3D castings that can be used as patterns in developing a Narrow Gauge large scale version.  In order to accomplish that, I’ll need operating running gear and I’ll need to do a scale conversion.

It is ironic that you cold look at Bill Thomas’ conversion of a Baldwin 4-4-0 to be a kit bash of a 1:1 kit.  He had the lower part of the engine,  All he had to do was build the upper part of the engine and the tender.  Fortunately Bachmann makes a 1:20.1 Baldwin 4-4-0.  I happen to have three, all old timer versions.  I intend to take one of those three, strip it down to the running gear, and build the upper part of the engine as well as the tender, using scaled take-off dimensions from the kit.  One of my 1:20.1 4-4-0s is already stripped down to the running gear.  I also have a running start on the tender.

Why build two models of the same engine?  Because it is my model railroad engine Holy Grail.   Because I have a tremendous amount of prototype information on that engine so I’m ideally prepared to build it.

The posts that follow contain additional prototype information.  They also contain my step-by-step of building the Wiseman HOn3 NPC No 21.  They will also contain the step by step for building the 1:20.1 running version once this project reaches that point.

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