A Baldwin DT6-6-2000 in HO – Project Update And Release

In my post, two weeks ago, I said that the HO D6-6-2000 project was just about ready and I was just waiting for the etched brass to arrive so I could do a test fit.  Then it would be released last week.  Well as you may have gathered from the last week’s absent post there was a little more work required before I could release the models.  But they’re now ready.

The etched brass arrived and looks very nice. It’s much thicker than my normal N Scale etches, and this gives it a sturdy feel.

However, because it’s thicker there was an added complication I didn’t foresee. To etch the metal, it’s done in two halves.  The front is half etched, then the back.  Any areas which are etched from both sides will form a hole.  All etching will have a rounding to the etched side, and the thicker the metal, the larger the rounding.  Normally for my thinner N Scale etches this has been insignificant, but for HO this means all the handrail and grab iron posts that fit into the 3D printed holes, didn’t fit as smoothly as designed, causing the etched parts to bend if forced in.

This is easily overcome by increasing the square hole size in the 3D printed model.  The larger hole won’t be visible once the brass is fitted, but it will make the fitting much easier.  For my test print, I’ll need to drill the holes to fit the brass parts and I haven’t gotten to that yet.

As I was making these modifications to the 3D model I also took the chance to make some other improvements.  The side handrails, as shown below, fit into a hole next to the cab door and two holes in the raised deck.  But alongside the lower deck, they were originally located by a small vertical block that represented the handrail fixing, but this didn’t set any height. So I have made the block an ‘L’ shape so the brass can be set in the correct position and ensure the handrail is level.  This will greatly improve the installation of the handrails.

Also in the image above you may have noticed I added the detail for the structural section which sits directly over the truck bolster.  This was missing on my N scale version.

Under the coupling in the pilot, there should also be a triangular-shaped section.  Looking through the photos I have of the originals it wasn’t always present.  I guess it was removable and not always replaced.  I’ve made this a separate part that can be attached to the Kadee coupling box if required.

So now I know all the parts work it’s time to let you know what you need.

To start you’re going to need a Bowser (Stewart) chassis from an Alco C628 or C-630.

The chassis looks like this:

Other chassis can be used if the mounting points and truck spacing are the same.  As shown below the chassis has a mounting point at each end.  The distance between the hole centers is 217.2mm (8.551″).

The chassis comes with different trucks depending on the loco model.

The C-628 should come with ALCo Trimout trucks which are what you need as a starting point.  The C-630 comes with ALCo Trimout trucks or High-Adhesion trucks; both have the gears required, but the base plate from the High-Adhesion trucks is shorter and won’t fit the DT6-6-2000 trucks.  But with a bit of modification, it can be made to fit.  (I’ll cover that in a later post).

Although the Baldwin RT-624 and possibly some later DT-6-6-2000 had trucks very similar to the Trimout trucks, the bulk of the DT6-6-2000s had Commonwealth trucks, so you’ll also need to get a set of the Bowser side frames.  I recommend the Bowser kit 96-603; it can also be used to upgrade an older Stewart Chassis to better pickup if that’s the one you have.  It can be found at the bottom right of Bowser page using the link below


If these become hard to get let me know, I can make a 3D printed set of side frames available.

To convert the Bowser Trimout or High-Adhesion trucks to Commonwealth, you’ll need my conversion kit which contains four truck center halves and 8 gears and can be ordered from Shapeways using the link below.


Next, I’ve made the small parts as a separate model; this was the only solution to getting them to 3D print properly.  This model contains the crew and cabs, horns, and triangular pilot blocks I spoke about earlier.  This can be ordered from Shapeways using the link below.


All the brass is on one fret and is ordered directly from me at a cost of £10 GBP each plus postage.  Please contact me directly for these.  I’ll add a page to the website soon.

The couplings for this locomotive has been designed as Kadee #148 HO Scale 140-Series Whisker® Metal Couplers with Gearboxes – Universal – Medium (9/32″) Centerset Shank.


To make the couplings powered you’ll need the Precimodels kit.


Lastly, you’ll need the shell.  So far I have three different versions available.

Baldwin DT6-6-2000 HO Type 1 has no window shades or frames and the horns are further forward in the roof.  This is to model the Baldwin demonstrator, No, 2000. ()

ATSF 2600 before any rework. (Uncredited image – it was in a magazine but I have no idea which one, so if you know where this image originates from please drop me a message).

Elgin, Joliet, and Eastern Railway early DT6-6-2000s such as no, 104 shown below. (Uncredited image – If you know where this image originates from please drop me a message).

My Baldwin DT6-6-2000 HO Type 1 can be ordered from Shapeways using the link below.


The Baldwin DT6-6-2000 HO Type 2 has slots above the windows for the brass sunshades and the horns have been moved back closer to the cab.  This is to model the early ATSF locos such as 2601 & 2602.  I think it’ll also work for some of the EJ&ER locos.

My Baldwin DT6-6-2000 HO Type 2 can be ordered from Shapeways using the link below.


The Baldwin DT6-6-2000 HO Type 3 has slots around the windows for the brass window box and the horns have been moved back closer to the cab.  The side plates under the cab have also been removed.

This is to model The Minneapolis, Northfield, and Southern Railway no 21. (Picture from Illinois Railway Museum http://www.railroadmichigan.com/illinoisrailwaymuseum.html)

The window box looks like this, I’ll do a post later to show how it fixes together.

Because the side plates have been cut back you will be able to see the model chassis.  I’ll  look at making a fuel tank section to cover this at a later date, this will also be used for the RT-624.

My Baldwin DT6-6-2000 HO Type 3 can be ordered from Shapeways using the link below.


There’ll be more shells coming over the next few weeks to cover:

The Trona Railway locomotives.

The Peabody Coal Railroad’s locomotives.

The Soo Line Railroad locomotives.

If you have a need for a DT6-6-2000 shell that I haven’t covered please get in touch via the contacts page.

A Baldwin DT6-6-2000 in HO – Project Update

It’s been several weeks since I last posted about the Baldwin DT6-6-2000 HO project but today I had some good news which means we are just about ready for release.

The bulk of the design and 3D printing has been done, as you can see from the photo of the successful test print below, but what was missing was the etched brass parts.

But today I had confirmation that they’ve been shipped from the etchers and I’m expecting them to arrive by tomorrow or Wednesday at the latest.  This means I can do all the test fitting this week, and assuming everything fits okay, I can release the full kit for sale in next Monday’s post.

The Baldwin RT-624 and some of the DT6-6-2000 varients are still being modified, but I should be able to release shells for Baldwin’s demonstrator, number 2000. ()

Elgin, Joliet, and Eastern Railway early DT6-6-2000s. (Uncredited image – If you know where this image originates from please drop me a message).

Santa Fe’s early models. (Picture from http://www.snowcrest.net/photobob/sfl2.html),

The Trona Railway locomotives. (Photo from Vernon Ryder, Jr.- collection of Mark Laundry – http://baldwindiesels.railfan.net/trona/index.html).

The Minneapolis, Northfield, and Southern Railway no 21. (Picture from Illinois Railway Museum http://www.railroadmichigan.com/illinoisrailwaymuseum.html)

And Peabody Coal Railroad’s locomotives. (Picture from Railrpictures.net)

There’ll be more as the variants get done, but if you have a specific DT6-6-2000 which you would like to model, please get in touch via the contacts page and hopefully I can make that shell available too.

I’m really looking forward to seeing the locomotive with all the brass fittings, I’ve just got to decide what color to paint the test print now!

Checking for Shorts when DCC Fitting A Wrenn Locomotive

The Wrenn Locomotives, despite being much older than most things you can get today, are still great locos and normally great performers.  They are not easy to convert to DCC but it can be done and I’ve previously written about the 3D printed sleeves I produce to allow you to do this.  But I sometimes get questions from customers who’ve done the conversions themselves, with my sleeves, and the loco runs very poorly even though it ran well on DC.  In this week’s post, I’ll show you what the most common reason for this is.

Coincidently this week I’ve had two Wrenn locomotives in for DCC fitting so I can use them to point out the issue.  The two locos, as you can see below, are a former LMS Duchess 4-6-2 and GWR Castle 4-6-0.

As well as being very different models visually they are different mechanically as well; the Duchess chassis at the back has a vertical motor and I covered the DCC installation procedure for this here.  The Castle has the horizontal motor and that was covered here.

Before I go any further I should point out one other issue which can cause problems with DCC fitting these locomotives and that is the current draw.  Sometimes older motors, and worn-out motors, can draw lots more current than intended and the DCC decoder can’t handle it.  To find out what the amperage draw is for a locomotive a stall test should be done.  You can read how to do this here.  Both of these locomotives had a stall current of less than 1 amp, so they are ideal for DCC fitting.

So what is the main cause of problems with these?  Starting with the Duchess below you can see I’ve cut off the wires as per the DCC install instructions.  Both motor brushers are still fitted and you can see them touching the collector on the armature.  The left brush holder, which is at the front of the locomotive, is isolated from the chassis, and the right, or rear one, is not.  The problem is often that the left/front brush isn’t totally isolated.  The brush still fits inside a brass sleeve which is wrapped in a rubbery paper-type material to create the isolation.  Over time, remember I said these were old, this material breaks down.  It’s possible heat from excessive running has affected it as well.  The material hasn’t totally disappeared and it’s not a dead short, otherwise the loco wouldn’t run at all, but a very tiny intermittent electrical short happens between the brass sleeve and the chassis.  Running the locomotive on DC doesn’t really affect it too much.  Although it’s not good for the controller, the tiny short will affect the running, but the controller is able to push more amps through the motor to compensate. But under DCC, the decoders are much more sensitive to shorts and are not capable of delivering as many amps.  The result is the locomotive runs very slowly or has no pulling power.

To check to see if this is going to be a problem remove the brush cap, spring, and brush from the left/front sleeve and inspect the insulation.

If it appears to be okay, basically not falling out, an electrical test with a multimeter can be done.  A continuity test, setting the multimeter to the symbol shown below, will check to see if there’s an electrical connection between the meter probes.

With the brush removed and the brush cap replaced, check to see if there’s anything between the two brushes.  This doesn’t work with both of the brushes fitted, as there’s a connection through the motor.  If, when performing the test, the multimeter gives the slightest suggestion that there’s a tiny connection there, it will cause a problem.

The solution for this is to remove the brass sleeve and isolating material and fit a 3D printed sleeve to the left/front as well as to the right/rear.  As the new sleeves are plastic you are guaranteed to have no short.  The customer’s Duchess above is actually in very good condition and is perfect with no sign of a short, so I won’t change the front sleeve, but once the decoder is fitted, if there’s an issue it will be changed.

The Castle with the horizontal motor can suffer from the same thing although it’s not so common. Both motor brush holders are at the back on either side of the motor.  Again I’ve cut the existing wires off but left the heavy gauge wire on the right, which runs from the connecting point to the brass sleeve on the right.  This is because it’s a better connection than relying on the spring to deliver the power.  The right-hand sleeve has the isolating material.

To remove the brush simply pull back the spring and it will slide off and the brush should fall out.

You can then do the same test as shown below.

I originally supplied my Wrenn DCC conversion sleeves in pairs to provide a spare incase something went wrong and one broke, but in hindsight I see it was a good idea as you may need to change both.  The sets I sell are:

Two Wrenn horizontal motor isolating sleeves.

Four Wrenn horizontal motor isolating sleeves.

Two Wrenn Vertical motor isolating sleeves.

Four Wrenn Vertical motor isolating sleeves.

Two Wrenn Vertical & two horizontal motor isolating sleeves.

This vertical motor design was also used in the Hornby Dublo locomotives, 2 and 3 rail, so should you wish to convert any of the locomotives to DCC or repair a DC locomotive which is shorting, the 3D printed sleeves will work.

Using Second Hand Capacitors

This week’s post will be a how-to for a question I get asked a lot.  Can I use second-hand Capacitors?

The reason I often get asked this is modelers often want to use second-hand capacitors to make StayAlive units for their DCC locomotives, and these can be very effective.  But where are they getting second-hand capacitors from?  Most electrical appliances have capacitors in them of one form or another.  A good example of this is an old stereo system I took apart for the motor.  Below you can see the main printed circuit board (PCB) and it has lots of black cylinders which are mostly all capacitors, and ideally sized to fit into small locomotives.

Even the smaller secondary PCBs have capacitors on them.

The main power input board below is a bridge rectifier, the smaller black cylinders are diodes, and it turns AC voltage into DC for the stereo to use, the nice big capacitor is there to smooth out the DC.

These capacitors are all soldered onto the PCB.  With a good soldering iron the capacitor can be removed without damage by heating the two soldered joints, once you have figured out which ones they are, and pulling the capacitor out. 

This capacitor has a working voltage of 24v and a capacity of 1000 microfarads.  The voltage is important because it needs to be higher than the voltage in the DCC locomotive decoder.  This normally does not exceed 16v, so a capacitor like this is ideal. 

But I find the more important question is not whether second had capacitors can be used, its do the work?  Luckily there is a simple test to check this without any expensive equipment.  Some high-end multimeters have the ability to test capacitance but most do not.  Mine does not, but what it can do is test voltage and resistance.

One thing to do before the test is to remove the charge from the capacitor, a full capacitor could damage the multimeter.  This can be done with a metal screwdriver by shorting across the two terminals.  Please note, this is okay for small capacitors in the Microfarad range used in modeling, I would not recommend doing this with large capacity capacitors with capacitance measured in farads!

The two settings I use are both on the left of my multimeter.  Below it is set to 200k ohms and is used for testing resistance.  I will also be rotating the dial clockwise by three positions to 2 which is a DC voltage measurement.

The way this works is first you discharge the capacitor.  Then, with the multimeter set to resistance, connect the probes to the capacitor.  Black negative to the capacitor negative and red positive to capacitor positive.  The capacitor negative is normally clearly marked.  As the multimeter has a battery inside when the probes are connected to the capacitor it will start to draw and store power.  As the stored power increases the resistance will increase so on the display you will see a steady increase in resistance from 0 to infinity.  If there are any big surges or erratic readings, then the capacitor is not working.

The second part of the test is to set the multimeter to volts DC and reconnect the probes.  This will measure the stored voltage and you will see it decease as the capacitor discharges through the multimeter.  Again this should be smooth.

As it happens the capacitor I took out of the stereo was faulty, probably one of the several reasons it didn’t work!

But to show you the principle, I created a short video of me testing a new capacitor.

So the answer to the question “Can I use second-hand Capacitors” is yes, but I would recommend testing them before spending any time wiring them into your locomotives.

If you have a similar question you would like to be answered or explained in more detail, please contact me and maybe I can help.

A New Drive Gear For an OO Airfix Class 14xx

This week I have another replacement part to share with you.  As with most of my replacement parts, this was a request from a customer who has one of these locomotives with a damaged part.

The Airfix class 14xx 0-4-2 model has been around since the 1970s, and was a mainstay on many UK model railways as they were the only maker of the model.  It’s had several upgrades over the years as the model moved to Dapol and then to Hornby but the original can still be seen running today.

However, constant use over time will always cause parts to wear out and with the 14xx it’s the main drive gear that starts to go.   The original chassis had a thicker gear which can be seen at the top in the image below.  The thinner gear is for one of the newer chassis introduced under the Dapol line.  Interestingly Daopol also moved the traction tire to the other wheelset.

The metal worm gear on the end of the drive shaft drives sits directly over the main axel drive gear and the metal eventually wears down the plastic gear, especially if the wheels get jammed up or start to bind, due to lack of lubrication.

The gear in the image below is still in good condition, but you can see the teeth are intentionally not square to the axle.  This makes the mesh between the two gears smoother and improves the running of the loco.

Using the original I was able to 3D model a replacement.  Because the gear is thick, 3.18mm, it should be strong and hard when printed in Shapeways Smooth Fine Detail material.

The test prints came out very well and were immediately ready to use.  The hole in the center has been printed slightly smaller than the axel size to ensure a good tight fit.  If it’s too loose the gear will spin on the axel. If it’s too tight the new gear may crack. To allow for any 3D print shrinkage or oversize on the axel, I’ve 3D printed two gears; one has an even smaller hole to allow for any differences mentioned above.  It’s always easier to remove material if it’s too tight than it is to add some!

To identify the two different gears I’ve marked the side of the gear with the smaller axel hole with a hole in the sidewall as you can see on the gear on the right.

The replacement pair of gears for the Airfix OO 14xx are available using the link here.

As long as I can find an original gear, even if it’s cracked or damaged, I can replicate it using 3D printing, so contact me if you’re in need of a new gear that you can’t get hold of.

Next week I hope to have some more to share with you on the HO DT6-6-2000 project, the brass etches are in production, and the different variants of body shells are being drawn.