Since this blog was started back in November 2013 the hope was at some point to turn this love of 3D printing model railway parts into a full-time business. The blog has built a strong following, with everyone from those who just read, to those who have become regular customers and friends. The response and support has always been very much appreciated. And you’ve enabled this to go from a part-time enterprise that grew from the love of a hobby to a full-time professional model railway business.

The only downside is the lack of time available now the business is full-time! It has very quickly evolved from a parts replacement and development business to a model railway building business. The working week is now full of working on customer layouts on everything from layout design, track-laying, wiring, to problem-solving and upgrading for more reliable and enjoyable train time. This is great news, but the blog has suffered; it hasn’t had the level of attention it deserves for a while because time has been taken away from 3D drawing and printing.

So please bear with us as we manage the balance between the smaller projects that helped get this business off the ground and the full days working in various houses, garages, attics, basements and spare rooms! The 3D printing side of the business is just as important; layouts are only as good as the trains running on them and making sure those run effectively is what started this whole thing.

In December of 2020, I first shared my ideas for the 3D printed wheel centers for the Bachmann OO split chassis 4MT. You can find the post here.

After two test prints, the design was finalized and a set was painted, I used a basic acrylic black spray. They were then ready to be press-fitted into the wheels.

The two with the larger counterweights go on the center set wheelset with the drive gear. No glue was required but I put a pot of superglue near the center of the wheel just to be sure. Be careful not to put too much otherwise it will squeeze out.

Once the locomotive was reassembled it looked as good as new.

Now the wheel centers are flat-sided the side rods no longer catch and the locomotive runs nice and smooth. This particular model also needed the axles replacing as they had cracked, the other common fault with split chassis locomotives of this era. The axle set can be found here.

These wheelsets are now ready to be ordered and can be found using the link below or can be ordered through the group order service, send me a message through the contacts page.

Bachmann Mainline Replacement Wheel Centers

But the 4MT is not the only locomotive with this issue. The Bachmann Mainline 2-6-2 tank also has this same design and many suffer from the bulging wheel centers. But the 2-6-2 has much smaller wheels, at 19.9mm diameter (equivalent to 10.4′), so a new design is needed.

The crank pin is also closer to the centre of the wheel giving a different shape to the centre casting.

The plastic inset pops out just as easily allowing me to take all the measurements I need to draw them up ready for a 3D print test.

These wheel centres will be test printed along with my next 3D print order. This locomotive also has cracked axles but luckily those are the same as the 4MT.

Next week I hope to have some more development work to share with you on the HO Baldwin RT-624 project.

With Christmas just around the corner, it marks the end of a very busy period for me and the start of a much-needed break.  But it won’t be a break from my trains or 3D printing, in fact it gives me a chance to get back into some of the projects which have fallen behind.

One of the projects I’m keen to get on with is the HO scale RT-624 and HO DT6-6-2000.  The RT-624, as shown below in N Scale, and the DT6-6-2000 have been very popular models and I’ve had a lot of requests to produce them in HO.  I did start this a while ago but was stopped in my tracks when Shapeways had their first big price re-structure which made the HO version very expensive.  But since they’ve had their second price re-structure the price now looks a lot more accommodating.

The other project which I’m keen to get finished is the N scale Union Pacific Rotary Snow Plow, number 900081.  I last posted about that in April of 2018, which surprised me how long ago it was!

In the new price structure, Shapeways have also made it not as expensive to print things the right way up as it used to be. This is important as it ensures the best surface finish where we want it, without costing the earth.

By grouping parts together I’ve also managed to bring the cost of models down and will be doing this with the new models.  This group of parts for a pair of Alco C-855 locomotives has everything in it except the main shells, and they’re all attached in places where it won’t show on the model, as well as having the best surfaces facing up.

Being able to do this with models has helped a lot and the difference is clearly visible.  Below is an N Scale EMD DD35, number 85B, which has just been finished for a customer.  It was printed the right way up and has a smooth finish enabling the paint to take perfectly.  This allows the decals to adhere to the model without any bumps, or areas that don’t stick and start to peel off when handled.  As well as the see-through corridor in the middle, it also has an ESU LokSound decoder with the twin motors which can be started independently from each other.  It looks and sounds fantastic.

I’ve also started looking into a new project that will make Santa Fe fans happy; I’ll share with you in the New Year, but I must finish the others first!

So I’ll be using the holiday break to get back to drawing again, but for now I wish you all a Happy Christmas and I look forward to sharing the upcoming work with you in the New Year.

In this week’s post I’m going to share with you one of the new products made by Peco, not only because I think the new product is worth a mention but also because there’s been lots of debate as to whether this new product is an improvement on the existing range as Peco will be replacing the others with this one.

Over the years Peco have made very reliable track work and I know it’s used all over the world. For example I know a museum layout in California which uses hand laid track on the public side and Peco in the hidden yards, simply because it works so well.  On our modular club layout, ‘Solent Summit’, Peco is our standard.

Peco have offered turnouts or points in two varieties in most scales for a long time,   Electrofrog and Insulfrogs; I’ve written posts before which help explain what the difference is.  The first was on how I improve my Electrofrog points for DCC operation which you can find here.  And the other was how I improve Kato points and that can be found here.  But the basic difference is Insulfrogs have a plastic frog which is the area where the rails cross, and also provide power routing. The post about the Kato points explains what power routing is.  Electofrogs have an all metal frog which improves power pickup but needs to be isolated from the other rails to prevent shorting.  This is normally done with plastic rail joiners or cutting the track with a disc cutter.

This means that Peco has two versions of every point, which makes production twice as expensive, and takes up twice as much room in the shops.  However there’s a big divide between modelers with both types being prefered for different reasons. The primary issue, I believe, stems from the age of the design which was originally built around DC operation.  DC operators like them as they are, DCC operators want them to change.  However DCC is fastly becoming more common and as I mentioned above I feel it necessary to always improve the turnouts for DCC operations.

So to resolve this Peco have combined the two types and now produce the Unifrog turnout.

The Unifrog has a metal frog, as the with the Electrofrog, but it is isolated at both ends by plastic strips.  The wire wrapped around the point is the optional frog feed, I didn’t unwrap it as this turnout is new and only borrowed for the post.

Up close you can see the isolators.  The wire, when unwrapped, is connected to the V section of the frog as well as the two check rails; this prevents any shorting from wide tread wheels which may touch both.

On the reverse side you can see Peco have also bridged the stock rails with the blades.  This is the main improvement I made to my Electrofrog points.  There is also a bridging wire connecting the blades with the outgoing rails next to the frog.  This means that power runs through the turnout in both directions without passing through the blade/stock rail joint irrelevant to the which way it’s set.  Perfect for DCC.

So what advantages does this give me?

• This turnout is ready to use for DCC or DC right out of the packet.
• I no longer need to use plastic isolating rail joiners on the two rails next to the frog.
• There is no danger of relying on power being transfer through the blade where they touch the stock rail.
• Compared to Insulfrog there is a large metal frog so no dead power section which affect small locos. (providing the frog has been separately powered)

What disadvantages does this give me?

• The turnout does not provide power routing compared to an Insulfrog point for DC operation.
• The frog will always be dead unless powered separately.

But, and this is the clever part, in order to make this work in just the same way as an Insulfrog turnout all you need to do is remove the bridges circled in red below.  This can be done with a screwdriver by braking the solder joint or cutting with snips.

Although this is not a modification I need to make, being all DCC, I think it’s a lot easier than the soldering modification to add them in. Yes, anybody wanting power routing now has an extra job to do, but it really is 30 seconds as opposed to the work required before.  This means, in my opinion, despite the compromise for the DC operators wanting power routing, the new points are a good replacement for both.

The dead frog disadvantage, also in my opinion, isn’t really a problem.  This is because for DCC operation it’s recommended to power the frog from a switch or electric frog juicer anyway.  And DC operators now have the option to power the frog which you didn’t with the Insulfrog which has to be an improvement.

Personally I thing this move by Peco is a good one and I’ll be using their new Unifrog turnouts on all my upcoming projects.

This week’s post will be a continuation of my step by step build of an N Scale A-B-A Ready-To-Run set of Alco C-855 locomotives.  And this post will be concentrating on the chassis and preparation required to get them ready to be assembled.  You can find part one of the build here.

The chassis for the C-855 and C-855B is a Con Cor U50/Turbine chassis and I have three ready for the job.

The first check I always make is to see how they run.  These are all in their original state and setup for DC operation.  Each ran well in both directions, although they make the higher than normal amount of noise these chassis tend to make.  The good news is later on I will be swapping the motors to solve this.

The chassis have lots of parts and striping down each chassis completely will be required as the base metal sections are going to be cut.  Removing all the parts will prevent any metal filings getting into the gears and stop any heat which may be generated warping the plastic.  If you’re going to be doing this with more than one chassis at a time I would recommend keeping all the parts for each chassis in separate bags or boxes.  I use old foil trays left over from baking vegetables, washed up of course.

I would also recommend numbering each chassis.  All the parts should be the same in each chassis but over the years Con Cor did make a few changes.  Plus the amount of miles each model has done can also affect how the parts fit and run together. A worn part and a new part may not run well together.

The main sections are the top and bottom metal parts and as you can see below with 3D printed extension parts.  Note each extension part has an arrow pointing to the front of the locomotive, and the orientation does make a difference.

You should always start with the top section as this will correctly set out the spacing of the two ends once cut.

I have marked the area to be cut out with a Sharpie pen.

The important surface is the step in the frame marked by the red line.  The 3D printed extension needs to butt up to this in order to make the chassis the correct length.  The area to be removed needs to be 2mm (1/16″) or less from this step.  If it is longer the remaining metal will push the extender away and over lengthen the chassis.

As well as the center section there also needs to be some cutting done at the nose.  Note: the A units need to be cut differently to the B.

Because both the Con Cor U50 and the Turbine have wide areas under the cabs which extend right to the front of the locomotives the chassis is wider here.  But the C-855 does not so the ‘wings’ at either side need to be cut off. Also two notches need to be cut out as show by the marked area below.  The nose needs to be 8mm (5/16″) wide, or less, and cut back by 7mm (1/4″).  I tend to use the hole in the front left side as a guide, this makes the notches a bit bigger but that’s fine. (Too small and the shell won’t fit).

To cut the chassis I use a bandsaw but this can be done with a cutting disc in a Dremel style tool.

As you can see the 3D printed extension is much larger than the cut out part.

The nose section, for the A units, looks like this.

For the B unit the ‘wings’ need to be cut off only, not notching. You will see this later.

Test fitting the extension you can see the two areas which butt up and there is a small gap where the cut was made which is exactly what is needed.

The three sections can now be fixed together.  I use an industrial superglue and a spray actuator as it’s fast and strong but you can use any good strong adhesive as long as it’s not designed to be flexible.

Because there is a gap between the cut face and the metal extender this allows it to be filled with glue.

And that’s it for the top section.

You can see in the picture below chassis number 2 has been cut for the B unit as it doesn’t have the narrow nose.

The second part is the lower section of the chassis.  The 3D printed section holds the motor in place and because of the geometry of the part it makes it hard to get it in the right place.  But because the top section is already set at the right length we can use this as a guide.

When I marked up the chassis for the photos, as shown below, I actually made a mistake and marked the section too far.

The red lines, shown below, are where the cuts should be made.  Basically in line with the lower section.  So no dimensions, just follow the existing line.

Once cut the two remaining bottom sections can be bolted to the upper using the original bolts.  Don’t worry about fitting the plastic spaces as they will be coming apart again.  I would also recommend installing at least two bolts in each end to avoid any rotation.

The lower section will be a tight fit and will take a bit of forcing in but once in the friction grip of the original parts to the new section will hold it in place.  I then use a pair of pliers to align the bottom of all parts.  Once I’m happy with the position I also fixed it with superglue.

With the glue all set the two newly extended chassis halves can be separated.

The lower section of the B unit also needs an additional few cuts.  Most of the way around the lower section is a shelf which the shell sits on.  But at the front the shelf is not there as this is where the loco cab is.  As the B unit has no cab this shelf will need to be cut out.  I place the B unit top section in place and draw round it as shown below.

And just to make sure I fill in the bit which needs to be removed.

Because this is a step and not a through cut I can’t use the band saw for this so it’s back to the cutting disc in a Dremel style tool.  The first cut is made vertically down to the level of the step.

The second is horizontal.  The two cuts should just about meet and the part will break out.

Repeating this across the front will leave the desired shape.

I also cleaned the area up with a small grinding bit in the Dremel style tool.

And that’s it.  All six chassis parts area ready to be reassembled.

In next week’s post I will show you how to extend the drive shafts and fit new motors into the chassis.