New Gears For A Bachmann N Scale Street Car & Brill Trolley

This is a project that I started at the beginning of 2020 so it’s about time I shared it with you. The Bachmann PCC Interurban Streamlined Car has been around since 1983 and was released in a large variety of paint schemes and liveries. However, all the models released up until about 2000, when Bachmann upgraded the chassis, suffer from the same problem; the white plastic gears on the axles crack. In this post I’ll share with you my 3D printed replacements to fix this.

The PCC Interurban Streamlined Car, and similar Brill Trolley released the year before, share a similar chassis with the same trucks. The body is all plastic and clips over the metal chassis, which fills the body.

The underside is fairly basic and you can see all four axles are driven via gears. These are the gears that crack under the pressure of the metal axles press fitted into them.

With the body removed you can see the chassis, which is made of two halves and separated by Bachmann standard fastener and washer system. Should these brake I’ve made replacements available here.

With the two screws removed the chassis haves come apart and the trucks fall out, although the repair can be done without separating the chassis or removing the trucks if you wish.

The large drive gear in the centre of the truck doesn’t have any issues.

The wheels have a short axle which press fits into the gear, when fully inserted the two axles do not touch each other so the gear also forms the electrical isolation. The wheels should just pull out. If the gears are cracked they’ll come out very easily.

The original gears, as shown on the right of the photo below, are made from a material that’s prone to cracking and you can see the light change as it hits the crack in the gear. With the metal wheel inserted the crack opens up. This causes two issues; firstly the spacing between two of the teeth is larger than the rest and causes a bump as the gear turns or jams the other gear. The second issue is there is little friction between the gear and the axles so the gear may turn, but the wheel won’t.

3D printing a set of four to replace all the gears is the answer and given the small size of these gears, roughly 5mm (0.196″) diameter, the best material is Shapeways Smooth Fine Detail because of its accuracy and hard-wearing properties. All four have been printed on a sprue so they don’t get lost in the printer.

Unlike injection moulding the sprue doesn’t actually touch the gears, it just passes through the hole in the middle. This can easily be cut with side cutters and the gears are ready to use, although I would recommend cleaning out the hole in the axles of any 3D print residue before you use them.

Refitting the gears and wheels is fairly simple. Position the new axle gear inside the truck and lightly push the wheel axle through the hole in the truck and into the gear. With both wheels lightly fitted, press the wheels together to press fit them firmly into the gear, just don’t push them in too far. The inside distance between the back of the wheels, commonly known as the Back-To-Back dimension, should be 7.65mm (0.301″).

Even if only one of your gears is cracked I would recommend changing all four as it’s probable the others will crack once you start using it again.

And that’s it, the street car is ready to use. The set of four gear axles can be found here.

I have several new gears for different loco types and scales to share with you over the next few months, but if you have something that needs a gear, get in touch. Just like this project I started last year, I may have all ready done it!

Back To Work after the Summer Break

It’s been several weeks since I last posted but that’s not to say I’ve not been busy. Given the strange times we’ve all been experiencing over the last year and a half, including the necessary travel restrictions, I took the opportunity to do as much as I could away from the workshop this summer. And that’s included some model railway stuff which I hope to share with you when ready.

But for now I’m back in the workshop with my batteries re-charged ready get on with the existing projects which have been on hold, several locomotive repairs, new builds and new projects. And there are quite a few!

As each project gets worked on or finished I’ll be getting back into my regular weekly posts to share it all with you.

As for tonight I have just had a big clean up of my work benches and desk to make a start, let’s see what I can get done for next week!

A Baldwin RT-624 in HO – Now Available

This week, as promised, I’ve made the HO Baldwin RT-624 kits available to purchase. They’ve now passed all of my checks and had all the little improvements made.

There are two kits available, and both look very smilier but there are differences. Below is the first version.

This kit is for the early Pennsylvania Railroad RT-624 locomotives with the Trainphone. The kit has three parts; the main 3D printed shell, 3D printed detail parts, and etched brass Additions. The 3D printed detail parts and etched brass are the same for both versions.

The second version is for the later Pennsylvania Railroad RT-624 locomotives without the Trainphone. It also has some body differences such as a different headlight position.

The donor chassis used for this model is a Bowser C-628 or C-630, the kit does not come with this.

Please also note that these locomotives have the correct asymmetric trucks but they’re facing the wrong way round. It will work but in order to make it look right you will need to rotate the trucks. As with my DT-6-6-2000 kit I developed a 3D printed kit for rotating the bowser trucks and re-using their side frames. (Bowser sell the correct side frames as spare parts if your donor chassis has the wrong ones).

All the parts are available from the links below;

Early PRR HO RT-624 Body Shell

Late PRR HO RT-624 Body Shell

3D Printed Detail Parts (For both versions)

Etched Brass Additions (For both versions)

3D Printed Truck Rotation Kit (DT-6-6-2000 Kit also for all RT-624 versions)

Commonwealth truck side frames are available from Bowser with their kit 96-603; it can also be used to upgrade an older Stewart Chassis to better pick up if that’s the one you have.  It can be found at the bottom right of the 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.)

https://www.bowser-trains.com/instructions.html

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.

https://www.kadee.com/ho-scale-couplers-c-274_276_284/148-ho-scale-140series-whisker-metal-couplers-with-gearboxes-universal-medium-932-centerset-shank-p-298.htm

These locomotives have also been designed to receive powered Kadee couplings using Precimodels motors. To make the couplings powered you’ll need the Precimodels kit.

https://www.precimodels.com/en/

The last shell in the HO RT-624 range will be the single Minneapolis Northfield & Southern locomotive numbered Twenty-Five which I’ll soon have finished.

If you have any issue ordering or any questions please let me know. Ready-To-Run versions can be made on request if you prefer, please contact me via the contact page for a quote.

Now the kits are finished I’m going to paint up the two test prints. I have an ATSF DT6-6-2000 and an early PRR RT-624 which I think will look great, and I’ll share them with you once done.

A Baldwin RT-624 in HO – Part 6

This week I have the final stages of testing to share for the HO Baldwin RT-624 before it’s released next week.

The big news is the etched brass has arrived. Thanks to all of you who pre ordered, your etch will be in the post this week.

The etch fret contains handrails, sun visors, grab irons, windscreen wipers, train phone antennas and MU hoses.

All the parts for the HO RT-624 kit look like this.

You may also need the truck conversions to rotate the Bowser trucks in the donor chassis as shown below. These are the same as for the HO DT6-6-2000 model and when I release the RT-624 next week I’ll include a link for these.

Lots of the details on the RT-624 etch are the same as the DT6-6-2000 but I still wanted to test fit as much as I could. Please note that in the photos the shell and 3D printed parts haven’t been fully cleaned yet and the brass is not glued in, just resting in place.

The end handrails are half etch and half 3D print. For strength the etch parts pass through the 3D print.

The sun visors fit nicely into the angled slots in the shell.

HO RT-624 - Brass Test Fit 06

The side handrails all have holes or locating lugs to fit into and it fits well, but as you can see its a little bent. This is simply because I got a little over enthusiastic cutting it out. As the etch is thick, 0.5mm, it takes some force to cut. I cut mine out on a cutting mat with a large craft knife (Box Cutter) and the force bent the handrails. The trick is to put something hard and flat on top of the etch to prevent the part you are cutting out from bending up.

HO RT-624 - Brass Test Fit 07
HO RT-624 - Brass Test Fit 08

The grab irons are basically the same as the DT6-6-2000 but I’ve made a slight change to the holes which made them a perfect fit. I fitted them without bending. Once pushed all the way in they easily bent down. Each grab iron has a small lug preventing them from being pushed in too far. When fitted with glue these will be secure and strong.

HO RT-624 - Brass Test Fit 09

All four on the side are the same.

HO RT-624 - Brass Test Fit 10

The top grab iron doesn’t bend.

HO RT-624 - Brass Test Fit 11

The last check I wanted to make from the etch was for the MU hoses. Each end has eight and they push into the square holes in the 3D printed section of the end handrail.

HO RT-624 - Brass Test Fit 12

It looks a little out of line as nothing is glued in place but once it’s all painted and securely fitted I think they’ll look very good.

HO RT-624 - Brass Test Fit 13

I now have a few small details I want to tidy up on the 3D printed shell but it’s almost finished. Next Monday I’ll release the model in two versions. The PPR early version with the Trainphone and the later without. There will also be one extra RT-624 for the single Minneapolis Northfield & Southern locomotive numbered Twenty Five.

A Baldwin RT-624 in HO – Part 5

My apologies for the lack of posts over the last month but this week I have an update to share with you on the Baldwin RT-624 project; the test print has arrived.

The photo above shows the shell and parts after they’ve spent twenty-four hours in white spirit which was used to remove the waxy residue left over from the print process. Some of this residue has turned to powder and can still be seen on the shell. To find out how I remove this see my ‘How To’ post here. I will be doing that next.

The 3D printed parts included with the shell are the crew in the cabs, horns, pilot blocks, Trainphone receiver, and end handrails centers with walkways. As you can see below the receiver and walkways have broken away. This is not an issue but I will update the 3D model to ensure this doesn’t happen again.

The receiver is designed to fit into a ‘n’ shaped slot at the top right of the nose; there’s only one on the loco, the other end doesn’t have one. You can just about see the slot in the loco shell below.

The receiver fits perfectly and once cleaned up can be permanently fixed in place with a touch of superglue.

On the pilot beam in front of the nose you can see four holes; these are for the end handrails centers.

These also fitted perfectly and have the holes to receive the brass handrail section which will complete the nose handrails. But both handrail center posts should have a walkway between them; this is the part that broke away and which I will ensure is 3D printed as one part in future prints.

The reason they came apart was an incorrect joint in the computer model which has been fixed. For this model the parts have simply been glued back together with superglue. Superglue is ideal for this because it’s made from acrylic, as is the 3D printed model. Other glues may have an effect on the 3D printed material and plastic glues may melt it.

The floor tread pattern actually faces towards the nose of the locomotive; this is because when it folds down to allow loco engineers to walk from one loco to another, the walkway pivots at the lower connection so the pattern will then be facing up. The face you will see looking at the nose will be the underside of the walkway. The square holes are for the MU (Multiple Unit) hoses which will be on the brass Additions fret.

With the handrail centre section repaired it again fits nicely into the holes in the pilot beam.

Looking from along side the locomotive you can see the walkway patten. You can also see the radiators in the side of the shell and I’m very pleased with the finish on those. You can also see I’ve added a little material under each handrail location along the side which will ensure each fits in the right spot.

Before I went any further I was keen to test fit the shell onto the chassis and did hit one design flaw. A different feature from the DT6-6-2000 is the RT-624 has a longer walkway on one side for extra batteries and a hollowed-out area. I copied the modelling for this from my N Scale model not thinking about the HO chassis and as you can see below the chassis hits it.

But that’s why I do test prints. The problem is easy to fix in the computer model and I can make a correction to this shell so that it’ll fit the chassis. I think apart from that, the shell is looking good.

I have ordered the first batch of etched brass Additions for this locomotive, and thank you to those who pre-ordered these. Once they arrive I’ll be able to do the final checks on the shell and, if all goes well, the HO Baldwin RT-624 will be made available to buy.

Hopefully next week I will have a cleaned up test print to share with you fitted to the chassis.

A Baldwin RT-624 In HO – Part 4

With the test print of the HO Baldwin RT-624 now in production at Shapeways, I’ve turned my attention to the etched brass parts that will accompany it. As with the HO DT6-6-2000 these will be in 0.5mm (0.0196″) brass and will come on a fret containing the parts for all versions of the locomotive.

The etch contains side handrails, end handrails, sun visors, grab irons, windscreen wipers, trainphone antennas and Multiple Unit hoses.

The sixteen MU hoses across the bottom of the fret fix into the 3D printed end rail section, as shown below, with eight at each end. All the brass parts have locating holes in the 3D printed shell for ease of assembly and strength.

As with the DT6-6-2000 the price for each fret will be £10 GBP and I’ll be looking for some pre-orders to help cover the cost of getting the etch tool made. If you’d like to be one of those pre-orders please drop me an email at jamestrainparts@yahoo.co.uk or get in touch via the contacts page.

I hope the test print will be with me soon so I can share that with you and once the etched brass has been ordered the HO RT-624 will just about be ready to be released.

I’m still looking into 3D printed truck side frames for both the General Steel Castings Delta equalized trucks and the General Steel Castings Commonwealth trucks and hope to have those ready by the time the kit is available.