A Baldwin RT-624 In HO – Part 1

At the end of 2020 I released my HO model of the Baldwin DT6-6-2000, you can find the post here. But that wasn’t the end of the journey because just as Baldwin updated the DT6-6-2000 to the RT-624, so am I.

The Baldwin RT-624 is the natural development of the Baldwin DT6-6-2000.  Built between 1951 and 1954 the locomotive is classed as a transfer unit, designed for moving strings of freight cars between local yards in big cities.  It was a heavy locomotive, giving it great traction, and it had, for its time, a lot of horsepower.  Baldwin had started changing their naming convention for locomotives by this stage; this locomotive was sometimes called a DT6-6-2400 but Baldwin’s correct name was RT-624.  RT stands for ‘Road Transfer’, 624 stands for 6 wheels per truck and 2400 horsepower.  To achieve the extra 400 horsepower upgrade from the predecessor’s 2000 horsepower, Baldwin replaced the pair of 606SC supercharged diesel engines with their newer 606A supercharged diesel engines.  These each produced 1200 horsepower and were more reliable.

The RT-624 is very similar to the DT6-6-2000 and at first glance, you could be mistaken in thinking they were the same locomotive. Apart from things which you can’t see, such as the larger engine size in the RT-624, there are many differences. Below is my original model in N Scale of the DT6-6-2000.

Next we have the RT-624, again in N Scale.

The first thing that stands out to me is the large section under the cab that covers the fuel tank; on the RT-624 this has been removed. I assume Baldwin did this for ease of maintenance rather than cosmetic looks. Next, at the ends of the locomotive, Baldwin introduced a fold-down walkway to allow crews to pass between locomotives that were coupled together working as MU (multiple units). This split the end handrail as well as adding pipework for the MU equipment.

The trucks on some of the RT-624 locomotives were also upgraded to Outside Equalized trucks from the original Commonwealth trucks. Out of the twenty-four RT-624s made, twenty-three went to the Pennsylvania Railroad, and only the last eight, built-in 1952 and numbered 8724-8731, had the new tucks.

Another difference from the DT6-6-2000 was the walkways on the side. The DT6-6-2000 was almost symmetrical but the RT-624 had one walkway that was a different shape from the rest. This one had a longer raised section allowing for more battery storage under the walkway, which you can see on the left in the image below.

Another visual change that only appeared on some of the Pennsylvania Railroad locomotives was the Trainphone antenna on the roof. I say some of the locomotives because in doing my research I’ve found images of the locomotives with and without the antenna.  The Trainphone system was started in 1945 and was phased out around 1967 so it may be that it’d been removed from some of the locomotives. Below is a good example, PRR 8730 (one of the last batch with the Outside Equalized trucks) is shown with no Trainphone antenna. This photo was taken by Michael Sirotta at Frankford Jct., North Phila. It’s a 35 mm slide photo and dates from 1965 or ’66. (The image came from www.railpictures.net/)

The main body also had many small changes such as different grill positionings, headlight configuration, number board locations, and horn types.

The good news, as with my N Scale version, the donor chassis for both HO DT6-6-2000 and RT-624 kits will be the same. All the differences will be on the 3D Printed or etched brass parts.

I’ll be making shells available for versions with and without the Trainphone antenna for the PPR. I hadn’t planned on making 3D printed replacement trucks as Bowser makes both the Outside Equalized and Commonwealth trucks, but if they become hard to get hold of please let me know.

Out of the twenty four RT-624s made only one didn’t go to the RRP; this went to the Minneapolis Northfield & Southern and was numbered Twenty Five. Researching this locomotive, I noted that a lot of the changes above had not been included. As far as I can see, the only changes between MN&S’s original 5 DT6-6-2000’s and their only RT-624 was a different position to the headlight and a raised grill on the nose side. The large plate under the cab covering the fuel tank was already omitted on their DT6-6-2000’s. So for that model alone, if anybody would like one, I can simply modify the Baldwin DT6-6-2000 HO Type 3 model I already sell, so please get in touch.

I’ve already started working on the HO model and will have some progress images ready to share with you soon as well as a rendering of the model I’ll be sending for a test print.

Bachmann Mainline Replacement Wheel Centers – Part 4

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 pray. They were where 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. becare not to put too much otherwise it will squeeze out.

When and 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 falt 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 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 drawn them up ready for a 3D print test.

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

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

A New Ordering Service To Help With Shipping Costs

From this weekend I’ll be offering a group order service for anyone who wants to keep their shipping costs at a minimum.  This will be in addition to the usual method of ordering through the Shapeways shop.

From this weekend you can get in touch with your order and within the next five weeks, when we have a group order, I’ll place that order with Shapeways. If I have an order ready to go sooner, yours will be included, but whenever you order you’ll never have to wait longer than five weeks before your order is placed with Shapeways.

I’m offering this service as a result of the increased shipping costs from Shapeways due to the current global situation.  Many of the shipping companies have had to increase their charges and these have had to be passed on to the customers.  My service is also designed to help with the issue of Value Added Tax (VAT) and import charges now the UK has left the EU.  Customers who receive their 3D printed orders from the US print facility shouldn’t be affected by this.

These increased charges can be really frustrating when a part only costs about £9 and the shipping is more expensive than the cost of the part.  Because I order parts myself I can add any part you require to my order and bring your shipping costs down.  Then I can post your parts to you at a cheaper price with Royal Mail, I’ll explain how the VAT works in a moment.

Ordering any of my 3D printed parts has always been easy through Shapeways and their checkout page looks something like this.

The example above is for a set of my 3D printed long DCC conversion sleeves for Wrenn locomotives and you will notice that tax (VAT) has not been charged on the order.  This is because the parts are printed in Eindhoven in the Netherlands and Shapeways are currently not set up to collect VAT for the UK government. So the parcel will be stoped at the UK border and VAT will be charged on the contents and shipping cost.  The shipper may also charge a fee for doing this which makes the parts rather expensive.  If the destination is changed to an EU country you will see the tax is added on here.

So how will my new service work?  If, as per my example above, you would like the set of the four Wrenn long isolating sleeves, drop me an email or get in touch via the contact page with your request.  I can then quote for the parts plus the 20% VAT and the shipping cost from me to you using Royal Mail.  I will not charge VAT on the shipping cost and you will not have to pay any import charges.  So the total cost of the Wrenn parts including postage to a UK address will be £12.04.  I can send an invoice for the parts and your order will be added to my next Shapeways order.  My Shapeways orders will be placed at a maximum of every six weeks but some orders might be earlier depending on what I’m working on at the time.

This service also comes with a hidden bonus.  For example, let’s say you only needed three of the Wrenn long sleeves and one short sleeve.  Normally you would have to order two sets from Shapeways but I can order exactly what you need for the cost of one set.

There is also the chance I have some of the parts in stock and can send them out right away.

Of course, this service may not be to your benefit if, for example, you live in the USA as the Shapeways shipping is less, and so is the state tax, if any.

So by all means have a look and see what the price is to order from Shapeways direct, and if you’re in the UK don’t forget to factor in the VAT and import charges, then drop me a message and if I can help reduce the cost, I will.

As I said at the beginning of this post this service will be on a group basis, starting this weekend. When I have an order ready to go, yours will be included, but whenever you order you’ll never have to wait longer than five weeks before your order is placed with Shapeways.

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 Different Material for Gears – A Second Attempt

For several years I’ve been producing replacement gears in Shapeways’ Smooth Fine Detail, formally know as Frosted Ultra Detail (FUD).  But what about other materials?

Back in June of 2019 I tested a different material, Multi Jet Fusion Plastic or PA12.  You can find the post here.  This test was not successful, as you can see below, because the definition simply wasn’t there.

To be fair these gears were small, measuring only 4.38mm (0.172″) in diameter.

But this material is a lot stronger than the Smooth Fine Detail.  The Smooth Fine Detail is an acrylic and although it’s very hard, it’s brittle and impacts can cause cracking.  That’s why my replacement Bachmann HO 4-8-4 gears needed to be much thicker than the original.  The PA12 is a nylon plastic and some of its listed key properties are high strength and durability, as well as good impact resistance.

To give it a good test I needed to try a larger part and the ideal opportunity came along when a  customer wanted some replacement gears for an O Scale 3 Rail brass AC6 Cab Forward.  These 4-8-8-2 are huge and a lot of power is transferred to the driving wheels to be able to pull prototypical trains.  This particular model has an idler gear that runs between a metal worm gear and a metal axle gear. An idler gear is a gear that spins freely on an axle without turning that axle between two other gears, the purpose is either to change the direction of the second gear or to simply space the gears out. (Image take from https://www.notesandsketches.co.uk)

The original idler gear was plastic, and due to the constant wear from the two metal gears, had become damaged.

The reason for this gear being plastic rather than brass was it had a left-hand twist, as you can see below.  This is not impossible in brass but it’s very expensive compared to regular gears with straight-cut teeth.

But this sort of complex 3D geometry is ideal for 3D printing.  This gear has a diameter of 9mm (0.3543″) so is twice the size of the previous gear and has much larger teeth.  In order to allow for spares, several were test printed at once on my typical sprue.

The PA12 material has a coarser finish than the Smooth Fine Detail but given the scale of the components, this is not an issue.  As you can see below the new idler gear fits well into the AC6’s transmission.

After assembly, the locomotive had several hours of use with no problems at all, so in this case the PA12 material is a success. At the time of writing the cost of the set of five PA12 gears is the same as a set of Smooth Fine Detail gears.  When the PA12 was first introduced it was more expensive.  The base color for the PA12 is gray but the black, as used here, can be chosen for a little extra cost.

With this successful test, I now have another material available for larger gears that don’t rely on tiny smooth parts.  The point where Smooth Fine Detail will need to be used over PA12 will be different from model to model and will depend on things like teeth size, but I’ll endeavor to use this where possible.

I still have several new gears to try for projects I’m working on, but if you have a need for a gear that’s proving difficult to source please get in touch and hopefully I can produce it for you.

Solving Common Bad Running Issues With Kato Diesels

Kato makes some fantastic N scale locomotives and they run very well, that is until they don’t.  In this post, I’ll share with you the three most common issues I find as to why these reliable locomotives stop working.

There are of course typical things such as dirty wheels and track, but the three issues I’m sharing with you take a little bit more to fix.  They’re also common on other brands of locomotives that have similar parts.

The first issue has become apparent on this Kato SD40-2, as shown below. This model was custom painted by Paul Begg.  This is a 6-axle locomotive that picks up the power on all 12 wheels.  The power is transferred to the chassis halves via copper strips and then into the circuit board.

With the shell removed you can see the circuit board. This particular locomotive is DCC fitted with a Digitrax DCC drop-in decoder, but I’ve had the same issue with DC versions.

The circuit board or decoder drops into the chassis and pushes forward which clamps it in place and at the same time makes electrical contact with the chassis halves and motor contacts.  Below, you can see the decoder has slid back exposing the electrical contacts at the front.

Close up you can see the electrical contacts, and the slots in the chassis halves they slide into.  Ideally, this should be a tight fit requiring a little force to push the decoder forward.  The friction then prevents the decoder from moving and ensures good electrical contact.  But sometimes the decoder is a loose fit; this may because the DCC decoder is ever-so-slightly thinner than the original circuit board or maybe the chassis has been affected by the pressure of clamping the decoder.  The consequence is the decoder slides in and out easily, and the electrical contact is very poor.

The electrical contacts or pads on the decoder are copper, which is ideal to solder too, so to fix this issue I flash over the pads with a soldering iron to put a thin layer of solder on top.

The layer of solder can’t be too thick, otherwise, it’ll prevent the decoder from fitting at all. To get a thin layer I first use the iron to put some solder on, then I clean the iron tip on a wet sponge and quickly run it over the pad again. Excess solder will be removed on the iron, leaving a thin flat surface.  This may take one or two passes with a clean tip each time.

The decoder can then be pressed in.  It will take a good press as the pads are now thicker, but if it feels like you need to press too hard, rather than risk breaking the decoder, pass a clean iron over the pads again to remove a little more solder.

Once fitted the decoder should not move and you’ll have a solid connection, because the solder is softer than the copper and the chassis will dig into it.

The second issue I see a lot is to do with the actual pickups in the trucks.  The AC4400CWs below, again custom painted by Paul Begg, suffered from this.  The first fix above has already been done. This is one of the older chassis where the chassis screws need to be loosened slightly to release the truck.

With the truck bottom, and side frames unclipped the pickups will fall out.  Each wheelset has a plastic axle and metal wheels with a spike on the outside of the wheel.  The spike fits into the cone of the brass pickup.

The issue is dirt and crud that builds up inside the cup.  Below you can see two pickups from the same truck. I’ve cleaned the cups on the lower one.

To clean these cups I use tiny cotton swabs dipped in Isopropyl alcohol. These fit perfectly into the cups to clean them out.  Another alternative is a small Philips/positive drive screwdriver of a similar size.  One note about using Isopropyl alcohol to clean contacts: if they’re from a 3D printed truck, clean the Isopropyl alcohol off fully before refitting the pickup because 3D printed materials and Isopropyl alcohol don’t mix very well.

As well as cleaning the cups the wheel spike should also be cleaned and for this, I use a regular cotton bud dipped in Isopropyl alcohol.

The last issue is also to do with trucks and is something I’ve come across several times.  Below is another SD40-2.  The decoder is not loose in the chassis and the pickup cups are clean, and as you can see below it’s receiving power as the light is on.

However, if the front truck is lifted off the track the power stops.

Lifting only the rear truck shows the power returns so one or both sides of the rear truck is not working correctly.

This is one of the newer Kato chassis and the trucks simply pull out and clip back in.  When removing the trucks the drive shaft will also fall out, so be extra careful not to lose the bearing on the end of the worm gear as they will also fall off.  Should it fall off note that there is a tiny plastic washer between the bearing and the worm gear.

With the truck removed the problem becomes apparent; you can just about see it in the image above but it’s clearer below. The righthand pickup, with the cups in, has a post that stands up to make contact with the chassis copper strips and it’s bent.

Compared to the one on the other side you can see it’s pointing towards the truck rather than up.  This will prevent making contact with the copper strip and reducing the locomotives pickup by half on that side.  The solution is to bend it back into the right place and this can be done with a pair of tweezers or small needle nose pliers.

Now with the truck reinserted in the chassis, the locomotive should work with either truck on the track.  And with both trucks picking up power, clean pickup cups and a good connection to the decoder, the locomotive should run as well as new.

Clean wheels are also important, and a little lubricant on the gears is also a good idea while you have the trucks out.  If you’re wondering what oils or lubricants to use on the gears I’ve written a post about that which can be found here.