Category Archives: Davenport Dinky

Minitrains 0-4-0 Cab Modifications

Once the engine is disassembled it is time to make modifications to major components.  First, the cab.  It is a one piece styrene structure.  The tail light that is moulded into this part is rather silly, placed on the back of the bunker.  It will be replaced to a proper old time kerosene lantern.  The air vent at the top will be converted to a flip up opening.

0-4-0 Cab Before2


The side view highlights a significant number of changes.

  • The four round windows will be converted to square windows.
  • The bunker will be replaced with a taller and deeper bunker.  It will provide inside room for the DCC decoder.  Given that one of the responsibilities of the engine will be to haul oil cars to the kiln, it makes sense to model this engine as oil fired.
  • A side door will be added adjacent to the rear of the cab.  The door will have a shade above, a window in the top portion, and an arm rest.
  • The step will need to be repositioned and a more appropriate version scratch built.
  • Rivets will be removed from the cab portion and it will be converted to a wooden cab.

These changes will make the cab more representative of an American prototype.  Given that these changes will weaken the cab if all the cuts are done at the same time, the bunker will be removed and replaced before moving on to the doors.

0-4-0 Cab Before1

Squaring the Windows

The objective here is to change the shape but not the size of the windows as they need to work with both a taller bunker on the rear and the boiler on the front.  I tried two different techniques to square these round windows.  I won’t discuss the first technique as it didn’t work. Here are the windows in their original state.

0-4-0 Cab windows2


The technique that worked best for me is to get out my smallest square riffler file and start filing.  Once they were reasonably square, I used a sharp Exacto knife blade to finish them off.  In my case the windows don’t need to be perfect as they will be finished by bits of styrene to represent window casings.  These styrene pieces will make the window openings slightly smaller.  The photo also shows the tools I used.

0-4-0 Cab windows1

Remove Bunker

The next step was to remove the bunker to prepare for a larger deeper bunker.  I scored lines along the rivets ascending vertically from the bottom of the engine in the bunker area.  I used a trusted technique of dragging an exact knife backward.  I used a bit of rectangular brass tube to keep my score straight.  Ince i had deepened the score, I used a razor saw from the top of the bunker down to cut the top away from the cab.  At this point the razor saw is half way through the bunker.

0-4-0 Cab Bunker1JPG


I then used my Exacto knife to finish the cuts along the scores.  To ,my surprise, I ended up with three pieces.  On the left is the cab, less bunker.  Top right is the frame around the bunker.  Top bottom is the bunker.  That piece includes the two holes into which the screws holding the rear pilot are inserted.

0-4-0 Cab Bunker2

This means when I build the new pilot and bunker, I’ll need to consider how the pilot will be attached.

I got out my calipers.  You might recall that I intend to place the Digitrax DN136D DCC decoder inside the new bunker.  Its dimensions are 0.55” x 0.404” x 0.2”.  I first checked the width of the new opening.

0-4-0 Cab Bunker3JPG

If I lay the decoder on its side (the longest dimension at 0.55″), it should fit nicely.  I then checked the height of the opening.

0-4-0 Cab Bunker4JPG

The second longest dimension is 0.404″.  I don’t want the bunker to be that deep.  So the height of the opening needs to be increased.  So I got out my Exacto knife and scribed a line across the back that would increase height of the opening.  Once the scribe was deep enough I used the Exacto knife to cut vertically to the line.  A bit of a work with the file resulted in an opening that is 0.484″ tall.

0-4-0 Cab Bunker5JPG

Building the New Front and Rear Pilot

The old rear pilot was 0.25″ tall by 0.25″ deep by 0.75″ wide at the top.  It was tapered a bit making it narrower at the bottom.  The old front pilot was 0.25″ tall by 0.27″ deep by o.65″ wide at the top.  Like the rear pilot it was tapered making it narrow at the bottom.  The narrower width allowed the fronts of the cylinders to be seen.

I will make the rear pilot out of a 0.25″ by 0.25″ by 0.75″ solid wood piece (like the prototype) and machine it to hold the coupler.  

Building the new Oil Bunker

The oil bunker needs to be at least .20″ deep to accommodate the decoder without protruding into the cab, although there is some room behind the motor for a protrusion.  The old bunker was about 0.1″.  We don’t want the oil bunker protruding beyond the rear pilot (unsafe in a crash), so the bunker will be built 0.20″ deep on the outside, making it slightly less than 0.20″ inside.  Cab wall thickness is 0.04″, so the bunker will be fabricated from 0.04″ styrene.  If I create cover the joint between bunker and cab using a small strip of the same material, the opening will be narrowed to 0.56″.  I’ll wait until the decoder arrives to see whether this will work.


Minitrains HOn3 0-4-0T Saddle Tanker

In its later years, the Sonoma Magnesite Company’s lone engine was a Davenport Dinky Saddle Tanker.  This is an image of the SMC Davenport Dinky.


This complete view shows a typical consist.


This is another shot of the Davenport Dinky, this with the top cut off.


Davenport Dinkys don’t exist in HOn30.  So the search was on for a credible substitute.  This is an image of a Minitrains Baldwin prototype saddle tanker.  Engine length appears to be similar to the Dinky is but the saddle tank is longer.  But for my purposes it suits the bill.

MiniTrains Hon30 0-4-0T Saddle 1

Shot on the opposite side.

MiniTrains Hon30 0-4-0T Saddle 2

Shot with a mining car consist.

Minitrains Hon30 0-4-0T-1

Here us a shot that is weathered and detailed.

MiniTrains Hon30 0-4-0T Saddle 3

These engines are out of production.  Fortunately I found one that had never been run on eBay.    What follows are my photos of the engine.

O-4-0T Saddle 5

This was shot with the engine on its side.

O-4-0T Saddle 4

Unlike the 0-4-0T that is in current production, the drive train is riveted rather than screwed together.

O-4-0T Saddle 3

There are only two screws visible on this engine.  I have not attempted disassembly and may not need to as I anticipate making no major modifications to the boiler, drive train, or cab.

O-4-0T Saddle 1

The unlike the Dinky, saddle tank goes to the front of the engine.  The front end could be upgraded with a number board, a more appropriate pilot, and a generator.

O-4-0T Saddle 2

Note from this rear shot that the motor takes up much of the interior of the cab.  It is curious that this engine has no fuel bunker.  Of course adding a bunker would provide a place to hide the DCC decoder.  The rear pilot and coupler would need to be redone.  A portion of the rear windows might need to be filled.

O-4-0T Saddle 6

This shot shows the decoder next to the rear of the engine.  With a bit of excess shrink wrap trimming, it can be made to fit.  Wires can be routed through holes in the back of the cab below the windows.

Converting to DCC will require engine disassembly.  More on this later.

Minitrains 0-4-0T Kitbash

This is my starting point engine, a Minitrains 0-4-0T, commonly available for around $50.  Major kit bash targets in this photo are the domes, the round windows, the headlight, the smokestack the red wheels, and the front and rear pilot.  The motor needs to be toned down and wires tucked out of sight.  There is no obvious way for the crew to get into the engine.


Here is a front view.  The couplers need to be changed to knuckle couplers. While I’m at it a more representative pilot needs to be fabricated.  A bell and a more obvious whistle need to be added.  The domes need to be removed and replaced with more American units.


The first step in bashing this engine is disassembly.  As extensive modifications will be made to the cab, the parts inside the cab need to be separated.  The action starts at the top of the engine.  The smoke stack screws into the frame of the engine from the top and is one of the major parts holding the engine together.  It can be removed by turning in a counterclockwise direction.  In this photo the other end of the screw is shown.

Koppel 0-4-0T Bash1

The rest of disassembly occurs with the engine inverted.  The other major screw holding the engine together screws into the bottom of the steam dome at the top of the engine.  This screw can be removed by turning it counterclockwise using an appropriately sized Phillips screw driver,  Once removed, the front beam can be pulled forward and out.

Removing the two piston rod screws (Philips) and the Crosshead Screws (Phillips) is next.  The Crosshead screws screw up into the bottom of the frame.  At this point the pistons, and valve gear can be removed.  The motor should drop out of the engine.  Backing out the Rear Beam screws allows the rear beam to be removed.  The following shows the parts that you should have after these steps.  The engine shown at the top, of course, is a completely assembled engine.  Note that my engine came with two stacks.

Koppel 0-4-0T Bash 3

I intend to convert this engine to DCC.  While it is possible to remove the can motor from the drive train, I’m going to do a continuity check once the motor leads have been clipped to see whether the can motor is linked to the pickups other than through the two wires in the above photo.  I suspect the motor is electrically isolated.  If that is the case, no further disassembly will be required.

Detail Parts

In super detailing the engine I ordered a number of detail parts shown in this photo.

Koppel 0-4-0T Bash2

Parts already on hand shown in the photo include:

  • Hand rail stanchions from Cal Scale (190-604) – laying loose.
  • A Kemtron (K-830) number board (#14) – laying loose.
  • Cal Scale rope pull bell (19-261).
  • Two Kemtron (6007) Kerosene Headlamps
  • A Cal Scale (190-595) whistle.
  • A Cal Scale (6164) headlight bracket.
  • Two Micro Trains N Scale Short Shank Couplers (1015-1).

The following other products are on order.

  • A DIGITRAX {DN136D} DCC decoder.
  • 2 Pack Mr. Coffee (GTF2-1) wire mesh coffee basket.
  • A Detail Associates Fluted Steam Dome (8004)
  • A Detail Associates Fluted Sand Dome (8003)

You might be puzzled about the coffee filters.  I found a cool article on how to fabricate smoke arresters from these coffee baskets.  The Digitrax decoder is very small (.55” x .404” x .2”).  Removing the bunker at the back of the engine and replacing with a slightly deeper and taller oil bunker would create room for the decoder.  The steam and sand domes are N scale.  HO scale domes are way to big for this application.

These parts along with small pieces of wire, brass, and styrene should give me what I need to turn this engine into an Americanized model.