Alco C-855 N Scale Replacement Lifters

Sometimes trains get damaged, I’m sure it’s happened to most of us at some time.  And there’s always that one point on a model which is more prone to getting damaged than the rest.  On my C-855 shells it’s the lifters at the rear of the model.

The C-855 has four lifting points to allow the whole body to be lifted off the trucks.  There are two in the nose and two at the rear. The nose lifters can be seen below; there’s a recess behind the hole to allow a lifting shackle to be attached.

The rear lifters are raised up on posts.  This is to keep all four lifting points at the same height.  On the real locomotive the posts would have been thick heavy metal but in N Scale acrylic they’re a little thin.  And it’s these that are likely to break if the shell is dropped.

If you can find the broken part it’ll fix right back on with a drop of superglue as this material usually breaks with a clean edge.  Injection moulded parts tend to distort when they break so fixing them back on can be harder.

But if you can’t find the part a replacement is needed so I’ve created a set of four lifting posts as the C-855B has four posts because it has no nose.

The set has two left and two right hand posts and they are all 3D printed on a ring which makes them a single part and therefore cheaper to print.  I’ve made them longer than normal so they can be shortened to the right length depending on where the break is.  As the material is hard these will not cut like injection model plastic but can easily be filed or sanded to get them to the right length.

The replacement C-855 lifters can be found here.

EMD DD35 with Body Mount Couplers – Part 3

Back in January of 2019 I shared with you my test print for an EMD DD35 with body mounted couplers in N Scale.  You can find the post here.  This week I thought you’d like to see what it looks like with a bit of colour.

The shell, as pictured below, is stark white having been 3D printed in Shapeways’ Fine Detail Plastic, also know as FUD (Frosted Ultra Detail).

With the pilots 3D printed as part of the body, the only two parts are the main shell and the fuel tank.  This locomotive will be Southern Pacific 9900.

But, as with most SP locomotives this one won’t stay this clean for long as it’s going to be weathered.

Weathering can be done in many different ways, and to many different levels.  This locomotive will be weathered with enamel paints using an airbrush, and typical for the SP it will bit fairly grubby.

The locomotive will now need a good wheel clean to remove any paint, as it always gets on them, and then it’ll be ready to run.

The DD35 kit with body mounted couplers is available here.

Bachmann N Scale 4-8-4 Replacement Gears – Part 2

In February of this year I shared with you my set of replacement 3D printed gears for the Bachmann N Scale 4-8-4, 3rd Generation.  You can find the post here.

At the end of the post I needed to make some modifications to the gears as the axels were still a little too loose on the wheels and the twin transfer gear was way too loose.  These changes were made and another set was 3D printed.

This time all the gears fitted well into the chassis, but I think I still have a problem with the twin gear as the motor struggles to drive all the gears.  Either the larger set are oversize, causing resistance between the gear and the worm, or the smaller set don’t have a deep enough trough between the teeth, which means the axel gears push the twin gear up into the worm.

With the original twin gear fitted, and all the other 3D printed gears fitted, the assembly runs smoothly.   Below you can see the axels fitted onto the wheels with the chassis plate installed.

With the entire chassis assembled I started testing the gearing and discovered that there was a bind at the same point in every rotation.  After a little adjustment I was able to get it to run much smother.  However, on reflection the next time I do this when fitting the gears to the first set of wheels, as shown above, I’ll attempt to get the gears positioned at the exact same point on each wheel, as I think it was this that caused the issue.  If, as with diesel locomotives, there are no side rods, the position of the gears is not so critical as they will find their place.  Or if there are no internal gears, simply side rods as with the HO 4-8-4, then it’s just the quartering which needs to be correct.  But as this loco has both internal gears and side rods, the quartering needs to be correct as does the gear positions relative to each other.

Below is a quick video of the chassis running with power supplied direct to the motor.

I’ll make the adjustments to the twin gears and do another test print, but in the meantime if you’re keen to get your N scale 4-8-4 back on the road and are happy to use all the other gears then a set is available here. In most cases, these 3rd generation 4-8-4 locos only need the axel gears to make a full repair as it’s the axels that split.

Once the new set arrives I’ll update you with the progress in a later post.

Fixing a Mainline OO Gauge J72

The Mainline J72 0-6-0 has been around for many years; it first appeared in the Mainline catalogue in 1976, and it was also my very first electric model train.  However this locomotive suffers from the same problem as most of the other Mainline locos; split gears! So in this post I’ll show you my solution for fixing this problem.

The J72 has a motor, which fills the cab and drives the rear axle.  The two forward axles are driven from the side rods so only the rear axle has a gear.

The wheels and side rods are handed, that is to say they are not the same on each side but mirrored.  If you look closely you can see a small section of metal above each pin where the side rod connects to the wheel.  This is to represent the oiling point for the bearing which the real locomotive would have had.  It also helps us to work out which side the wheel sets go.  The side rods are also in two pieces and the two parts connect at the centre wheel.  The rear side rod fits over the front.  It’s important to get this the right way around as the axle spacing is different with the front two being closer together.

The original rear axle with the gear and two regular axles are made from a black injection modelled plastic and looking closely you can see they have all split.  This causes the wheels to spin freely in the axle and consequently jamming the side rods.

To solve the problem I have designed a 3D printed gear and axle set to be a direct replacement.  These have been 3D printed in Shapeways Fine Detail Plastic because of the material’s accuracy and toughness.

They are all 3D printed on a solid bar to keep them all together but the axles are loose. When the bar is cut they will fall off.

The original main gear I designed was a direct copy of the Mainline part, but because of the recess to reduce the amount of material used, this caused a week spot in the 3D printed gear.  Although the Fine Detail Plastic is tough, it’s also brittle at thin areas.  When the wheel was pushed into the gear it broke. So the gear was redesigned to be a bit thicker and the recess was omitted.

When fitting the new axles it’s vital to get the quartering correct.  A description of what this means can be found in my post about ‘Bachmann (Mainline & Replica Railways) Split Chassis Axle Repairs‘.

It’s also important to get all the wheels aligned, as shown below.

The new axles will press-fit onto the wheels and should be pushed all the way on.  I get the axle started then double check it’s at the right position before pushing it all the way.  It’s possible that the axles may have some 3D print residue left inside.  This can easily be removed by reaming the hole with a 1.9mm drill.  If you use a larger one you’ll open the hole up too much and the axle won’t grip the wheel.  It’s also worth double checking you have the geared axle on the right wheel set and the right way around as it’s not symmetrical.  In the image below you can also see the thicker gear from the new design.

Assuming the quartering is correct the repaired wheel sets should drop into the chassis returning it to a working locomotive.  If, once all reassembled, the locomotive lurches or makes a thumping sound at the same point in every wheel revolution then the quartering is out on one of the wheels.  This should be visible be examining the wheels; one will be at a slightly different rotation to the others.  It’s possible to adjust this without taking the locomotive apart.  Hold the correct wheel tight with your fingers and carefully rotate the wheel on the other side,  It should slip in the axle.  Only make small adjustments and retest each time.

The new set of axles & drive gear for the Mainline J72 is available here.

In next week’s post I’ll have part two of the post for the replacement gears for the Bachmann N Scale 4-8-4.

Bachmann HO US 4-8-4 Replacment Axle Shafts & Gear

My apologies for not posting last Monday, unfortunately a loved one was involved in an accident and we didn’t leave the emergency room untill 9pm. All’s well and they’re on the mend so let’s get back to normal.

Last year, coincidently about this time, I shared with you my designs for replacement axles for the HO Bachmann 4-8-4.  You can find the post here.  This week I’ve updated the 3D printed model to include the main drive gear.

The gear is less likely to split than the axles, but sometimes it does, so a set with everything in makes sense.

All the parts are joined on a 3D printed continuous bar so they’re all one part; this makes them cheaper to print, but the bar doesn’t actually touch the parts so there’s nothing to be cut off or trimmed as with injection molded parts.  This is one of the many things which makes 3D printing great.

The parts are also available separately and they can all be found in my Shapeways Shop or via the links below.

Axles & Gears

Axles Only

Gear Only

This coming weekend, 1st to 3rd March 2019, is the N Trak convention in Bournemouth, England and again it’s at The Trouville Hotel.  You can read a bit more about the 2017 convention here and the 2014 convention here.  I’ll be there over the weekend if you’re in the area and want to come by and say hello.

Replacment Gears For A USA Trains G Scale 0-4-0

In a similar post to last week I have another replacement gear to share with you.  This time it’s much larger and for a G Scale 0-4-0 Pennsylvania 20-Ton Diesel Locomotive; made by USA Trains.

Despite being a small locomotive it’s a big model, G scale has a model ration of 1:22.5, and is heavy.  This also means that the motor has lots of power and the transmission needs to be able to withstand the forces applied.

Both of the axles are powered from a worm gear on each end of the central motor. The worm gears drive plastic gears which also form the axles and isolates the two metal wheels from each other.  As you can see in the image below the plastic axle has split.  This means the motor drives the gear which turns but the gear doesn’t turn the wheels.

As replacement parts for this locomotive were not available I drew one exactly the same size as the original and 3D printed it in Shapeways Fine Detail Plastic, formally known as FUD.  As I’ve said in previous posts this material is ideal for gears as it’s hard-wearing.

The original gear was also a bit mangled as the softer plastic tends to get damaged by the metal worm gear when under heavy loads such as starting and stopping suddenly.  The new gear with the harder plastic can withstand this without being damaged.

The axles have grooved ends to enable them to grip the inside of the plastic axle.  With some evenly applied pressure they can be pushed into the new axle.  In the image below they need to be pushed in a bit further but you can see the grooves in the metal.

The locomotive motor is in the box between the axles and when the lid or base is screwed on the new gears are pressed up to the metal worm gears.  The motor box is not connected to the body but clamps to the axles which sit in sprung axle boxes.  This allows the locomotive to navigate bumpy track and gradient changes without losing traction.

Once the motor base is replaced the locomotive is ready to go back out onto the railroad.

The replacement drive gear can be found here.

They are also available in a pair here.

Next week I’ll have even more 3D printed gears to share with you but this time it will be for  N Scale.