Bachmann Mainline Replacement Wheel Centers – Part 3

A few weeks ago I received my first test print for my Bachmann Mainline replacement wheel centers, you can read the post here.  Although the first test prints looked good, one of the dimensions was incorrect, and consequently they didn’t fit.

This week I’ve received the second test print.  Again these have been printed in Shapeways Smooth Fine Detail Plastic.

Compared to the originals you can see there are four wheel centers with small counterweights and two with large ones.

This time the wheel centers fitted perfectly.  There was a little 3D print residue inside the crank peg hole which I cleaned out before test fitting.  The wheel centers are a snug fit and it’s worth bearing that in mind when painting; if the paint’s too thick it’ll prevent them from fitting correctly.

These can now be prepped for painting.  I do this by soaking the parts in Goo Gone for 24 hours, rinsing under a warm tap, and then leaving to dry for a few days.  Any 3D print residue left behind will turn to powder and can be brushed off.  I’ll then spray them black and re-assemble the locomotive.

As the wheel centers are a snug fit it’s unlikely they’ll fall out but as a precaution, I’ll put a few drops of superglue on the center of the wheel.  I wouldn’t recommend putting any around the outer rim or under the spokes as it’ll certainly spill out.

These are now ready to be ordered and can be found using the link below.

Bachmann Mainline Replacement Wheel Centers

These will fit the Bachman (Mainline) Split Chassis Standard 4MT, as well as any other locomotive that has a wheel diameter of 24.5mm (flange to flange) and an inside diameter of 20.6mm.

If you need a wheel center for a different locomotive, please let me know and I can make that available as well.

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

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 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.

Replacement Atlas N Scale Motor Universal Connectors

Atlas make lots of railroad locomotives and rolling stock in a variety of scales, and I have several of them because of their quality and they enable me to use the chassis for other builds.  In particular, I use their C-628 and C-630 N Scale models as the donor chassis for my N Scale DT6-6-2000 and RT624 kits.  The chassis has been revised over the years to make improvements, but one version has an issue with the driveshaft coupling to the motor failing.  In this post I’ll share with you my fix.

Below are a pair of Monon C-628s; the rear one is actually a dummy using my 3D printed chassis kit.

The powered chassis is a standard design, used on many of Atlas’s N scale locos, with a central motor and flywheels.

The chassis is held together by the two screws near each end, and the fuel tank, which clips over both chassis halves.

Inside at each end is a driveshaft linking the flywheel and the worm gear, which drives the truck towers. These simply pull out.

The motor is clipped in a cradle which in turn is clipped into the chassis.

With the motor removed you can see inside the flywheel; there’s a plastic universal joint, and it’s cracked.

The universal joint is press-fitted over the axel and uses the friction to spin it with the flywheel.  Even when cracked it’ll spin so the loco will probably run okay on its own.  But as the load is increased, such as adding a train, the amount of force on the split universal is stronger than the friction, and the axel just spins.  So if your loco seems to run okay, but won’t pull very much, this is most likely why.

The universal joint is a plastic tube with two pegs which fit into the driveshaft.  The hole in the tube will be smaller than the axel to create the required tight fit but the constant pressure on this particular material causes it to crack.

Replacement universal joints are available from Atlas, but these have been known to fail as well.  So I’ve 3D modeled the part and printed it in Shapeways Smooth Fine Detail plastic because it’s both accurate and also hard-wearing

The new part is a direct replacement for the original.

If the old universal is cracked it should simply pull off leaving a clear axel inside the flywheel.

I fitted the new universal by placing it with a pair of tweezers but not pushing it on fully, just enough to hold it in place.  If it’s pushed at an angle it too may crack.

I then used a flat screwdriver, as to give even pressure, to push it on fully so the universal is all the way to the back of the flywheel.

And that’s it.  The loco is ready to be reassembled.

These are now available in packs of two and four using the links below:

2x Replacement Atlas N Scale Motor Universal Connectors

4x Replacement Atlas N Scale Motor Universal Connectors

This universal is used in many of Atlas’ diesel locomotives and will fit all.

I’m juggling an HO project as well as testing recent 3D printed replacement parts, but my focus is on returning to work on customer’s layouts where possible, so who knows what I’ll be sharing next week!

Replacement Bachmann OO Chassis Fasteners & Washers

This week I have another new replacement part to share with you. A locomotive was brought in to get DCC sound fitted and I know from experience there’s a good chance certain parts will break when the locomotive is taken apart, and in this instance I was not mistaken.  The Locomotive in question is a Gresly V2  made by Bachmann under their Branch Line range.

These locomotives are very good, although now an older model, and are normally very reliable.  The primary problem these, and other locos in the range, suffer from is split axels and I’ve already 3D printed parts to repair them, which you can read about here.

However, the axels on this locomotive are fine; the issue is with the split chassis fasteners.  A lot, if not all, of the Bachmann locomotives of this generation, have a split chassis.  This means the chassis is in two halves with each side conducting power from the wheels to the motor, eliminating the need for wires.  For DC operation this is perfect.  But for DCC I need to separate the chassis halves to electrically isolate the motor.  The chassis halves need to be screwed together but electrically separated.  This is achieved by using a plastic chassis fastener, plastic washer and metal screw.  The fastener has a square head that fits into a square recess in the left chassis half to stop it rotating.  The washer fits between the chassis halves, over the fastener to separate them, and the screw pulls the parts together as it bites into the fastener.

The problem comes, as with this V2, when the locomotive has never been taken apart and the plastic fastener has either deteriorated or maybe shrunk.  I’m not sure what actually happens.  But the screws are very tight and the force needed to get it to move is often more than the fastener can take and the tube section twists off the square head; as you can see below.

Or the tube section simply breaks at the end of the screw, which also happened on this locomotive.

It is possible, if you’re both careful and lucky, to glue the parts back together, but more times than not it doesn’t work and I often come across these locos with several missing fasteners.

So my solution, as is my way, is to 3D print replacement parts.  I designed the fastener to be a direct replacement and included a washer as sometimes the originals can get lost.  They are 3D printed in Shapeways Fine Detail Plastic as it’s the most accurate.

Before these can be used it’s very important to clean out the tube section.  This is because it will be full of 3D print residue which, if left inside, will add pressure to the tube wall as the screw is driven in, cracking the tube.  To clean out the tube I use a 1.26mm (0.049″) drill in a pin vice.  This won’t actually remove any of the tube material, just ream out the hole, as you can see below.

There’s usually a lot of residue in the hole because it’s small and Shapeways post-cleaning processes can’t get in there.

With the fasteners ready the chassis can be reassembled.  The V2 uses five, as you can see below by the holes in the right side chassis half.

With both sides fitted you can see the square heads in the left side chassis half.  It was only when I put this photo up I realized I had the front one in the wrong way round.  Fortunately with that one it works from either side.

The square recess in the left chassis half has a bit of tolerance so the head will rotate a little.

These replacement fasteners and washers can be used on a large variety of Bachmann split chassis locomotives and I’ve made them available in a set of 6 here and a set of 12 here.

This particular V2 is now back up and running and has an ESU sound DCC decoder, working lamps, and a realistic firebox flicker whenever the fireman opens the firebox door, which reflects nicely around the cab.

If you have another part, such as this fastener, which has broken and you can’t find a replacement I’d be happy to see if I can draw it up for 3D printing.  You can get in touch via the contact page.

Replacement Bell Cranks for an MRC/Rowa N Scale 2-8-4 and 2-8-8-2

Back in May of 2015 I needed a replacement eccentric rod for an N Scale Rowa/MRC 2-8-4 Berkshire to replace a missing one on a second-hand locomotive, and designed and 3D printed the part.  The post can be found here.

Since then I’ve had a request to provide a replacement bell crank for the Rowa/MRC 2-8-8-2 Y6B.  This mighty steam locomotive was one of the original N scale greats dating back to 1969 when MRC first released it.

It went through a few changes and was re-released in 1977 by Con-Cor/Rivarossi.

One of the main differences in the two versions is the side rods and valve gear.  The original MRC, and later Rowa version had plastic parts, whereas the later Concor/Rivarossi ones had metal.  The part I’m replacing is on the earlier MRC/Rowa version, which coincidently is exactly the same on their 2-8-4 Berkshire.

The original Berkshire bell crank and eccentric rod are shown below.  They simply clip together and the bell crank rotates about the round lug, which is at the other end from the C section.

The new 3D printed bell cranks are printed on a sprue, simply because they’re so small.

Up close you can see the new 3D printed part is slightly chunkier than the original injection molded part to give some extra strength to it.  Once fitted it’s very hard to see the difference.

On the Berkshire, with the bell crank removed, you can see the circular hole at the back of the bell housing to receive the round lug.

The new part clipped right in and rocked back and forward with ease.  The part will ideally be painted silver before the final install.

The original eccentric rod clips into the new bell crank and the main drive wheel, fixing with ease, and that’s it.  This particular Berkshire has no motor in it so I can’t show it running, but it ran freely along the track by hand with no issues from the new bell crank.

The Y6B, as I said before, has the exact same bell cranks, just more of them.

The only difference is the eccentric rod is shorter, which is caused by the altered geometry of smaller driving wheels compared to the Berkshire.

A pack of 6 bell cranks for MRC/Rowa 2-8-4s and 2-8-8-2s are available here.

I’ve had some time to get around to finishing some other long overdue 3D printing projects and over the next few weeks, I look forward to sharing these with you and making them available to buy.