A Small Fix for the N Scale Alco C-855B

My most recent locomotive shell is the N scale Alco C-855B, the companion locomotive to the C-855 released a little bit earlier.  The C-855B is almost the same as the C-855 with the exception of the missing cab.  Along the sides of the locomotive are the iconic sandboxes and it’s with one of these that I’ve picked up an error in my model.  In this post I will show you what that error was and how it can be fixed.

The front end of the shell, as shown below, where the cab would normally be has a similar setout to the rear end.  The walkways, sandboxes and railings are the same and simply mirror the details already drawn.  However, the front sandboxes on the C-855 are different and also have a different fitting location.

Alco C-855B Sand Box Fix 1

When I drew the C-855B I took the model of the C-855 and modified it.  I did the front right-hand side first, followed by the left.  And it was at this point that I forgot to adjust the sandbox fixing.  In the image above it looks like there’s nothing wrong but in the image below you can see the long slot for the sandbox locating pin and the frame sticking down.  This slot should have been further to the left and a bit shorter.  Also the frame should have been pushed back all the way to where the walkway steps out.

Alco C-855B Sand Box Fix 2

To show this below is a screen shot of the rear of the C-855B with the correct detail.

Alco C-855B Sand Box Fix 3

So how is this solved.? Well, fixing the 3D model is easy and that has already been done.  The C-855B that’s available on Shapeways is correct and all the sandboxes fit.

If you already have a C-855 then there are three choices.  Firstly, you can cut or sand the locating nub off of the back of one of the sandboxes.  Then trim back the lower section by 3.5mm (1/8th inch) as shown below and it will fit.

Alco C-855B Sand Box Fix 5

Secondly, if you don’t fancy cutting the 3D printed material, I have made a replacement sandbox available on Shapeways, which will be a perfect fit.  In the image below you can see it on the right compared to the original on the left.  The locating nub has been moved over to fit into the hole in the shell and the lower section has been cut back to make way for the frame.

Alco C-855B Sand Box Fix 4

This replacement part can be found here.

The third option is to replace the shell and as with the C-855 I have made the C-855B shell available on its own with no other parts, which can be found here.  This is a bit extreme but if you have had an accident with your shell this is cheaper than buying the whole kit.

Hopefully those who have already purchased a C-855B can make the existing sandbox work without too much trouble.  However, I am happy to help so please feel free to get in contact me and ask any questions.

I know some of you are still waiting for the dummy chassis for this locomotive and I am hoping to have something to share with you very soon.

Geared Up and Ready To Go

At the beginning of June I shared with you some drawings for a replacement cup gear to be used with a Con-Cor U50/Turbine chassis.  That post can be found here. In this post I’ll show you the 3D printed result.

This new gear is a part used to extend the chassis for use with my Alco C-855 kit.  And this particular gear was designed for the rarer chassis made by Sekisui which has 26 teeth in the gear.  The normal one has only 20 teeth.

Below you can see a render of the two gears.

Alco C-855 Extra Gear

And below you can see the actual 3D printed gear.

New C-855 26 Tooth Cup Gear 1

In truth there isn’t much to see.  The priority was to make sure it fitted into the existing gear and matched the motor teeth, which it did, but it was a very tight fit.  So I decreased the diameter of the tooth section by just a fraction and reprinted the gear.  Now, as you can see below, it fits into the cup gear.  It’s a nice gentle fit and the motor teeth matched the other side.

New C-855 26 Tooth Cup Gear 2

So the last thing to do is to tell you where you can get them, and as usual it’s through the Shapeways shop.

Here is a link to the set of two 26 tooth cup gears for Sekisui-made U50/Turbine chassis.

So, a nice short post this week!  I’ll have something a bit bigger to share with you next week.

A Difference in Gears

This week’s post is about a replacement gear set for my C-855 model.  In particular it’s for the very early Con-Cor U50 chassis and the difference it has with later models.

The Con-Cor U50 and Turbine chassis has a centered motor powering two drive shafts.  Each drive shaft has a cup gear on the end which looks like this.

Con Cor 4500-U50 Chassis Render 2

The motor has a small gear which fits inside the cup.

In the rendered image below you can see the two drive shafts either side of the motor.

Con Cor 4500-U50 Chassis Render 4

My C-855 locomotives required this chassis to be extended and therefore the drive shafts as well.  In the image below you can see the white drive shaft extenders inside the extended chassis.

Alco C-855 Chasses 2

Up close you can see the drive shaft extender is simply a cup gear that plugs into the existing gear.  The tooth set out is the same with twenty teeth in total

Alco C-855 Chasses 8

So far in all the U50 and Turbine chassis I have seen the cup gears have all been the same.  But last month I had an email from a fellow modeller who had a U50 chassis with different cup gears.  His had 26 teeth per gear.  So I searched through all the U50 chassis I had to hand and eventually found one as well.  It looks like the very first U50 batch were made by Sekisui on behalf of Kato and it is these models that have the different gears.  Both the Kato made and Con-Cor “Rail Baron” version have the same motor gear and cup gear.

So not wanting to let anybody down I have drawn a replacement cup gear extender.

Alco C-855 Extra Gear

The new cup gear is on the left and you can see the teeth are finer, and there are more of them.

Before I release this gear I want to do a test print and check that it really does fit the 26 tooth cup gear in the Sekisui chassis.  Then it will be available through the shop should you wish to convert your Sekisui U50 into a C-855.

Also while searching through all the chassis I noticed the gears in the trucks and worm gear are different between the Kato made chassis and Con-Cor “Rail Baron” versions so I would not recommend mixing up the trucks, I tried it and the loco run very lumpily indeed!

Adding Window Glazing and Wipers to the Alco C-855

Last week I showed you how I added lighting to my C-855s.  The final details to add to the locos are the window glazing, and to keep those clean, the windscreen wipers.  In this post I will share with you what I did.

The glazing is fairly simple.  A use clear plastic sheet which can be cut with scissors or a sharp craft knife.

C-855 Glazing 1

I designed the inside if the window areas to be flat so the plastic need only be larger than the window and glued in place. For the front four windows I use one strip of plastic measuring 18mm by 6mm.

C-855 Glazing 2

For the two side windows you will need one square piece each measuring 6mm by 6mm.

C-855 Glazing 3And don’t forget the windows in the doors, that piece needs to be 5mm by 3mm.

Before you attempt to glue anything test fit each window with a pair of tweezers to make sure it fits.  This also helps to work out the best angle to put them in at because it’s a bit tight on maneuvering room.

I like to use Gel Control superglue made by Loctite.  Not only does this superglue give you about 12-15 seconds before it sets it also doesn’t run allowing you to get it where you need it.  However if you simply try to put it around the window frame or on the actual plastic with the nozzle it wont go well.  You will get two much and in the wrong place.  It’s best to put a drop into a bit of scrap paper, then use a toothpick to put an even smaller drop on the window frame.  You don’t need much as it will spread out under the plastic.  Also you don’t need to go all the way around, two or three places will be fine.  The more glue you put on the higher the risk of it spreading out or smearing over the part you want to be the window and that doesn’t look so good.

Once all the windows are in place, and stuck, its time to add the windscreen wipers.  I sprayed the brass parts before removing any from the fret, it’s much easier that way.  The wipers are in pairs and handed.  Looking from the front of the fret, the wipers below are for the right hand side, the longer one is for the outer window.

C-855 Wipers 1

Once the wiper is removed you will notice a small half etch on the back of the arm.

C-855 Wipers 3

This is where you bend the arm to fit it into the hole in the shell above the window.

C-855 Wipers 6

Then it’s simply a matter of adding some glue to the arm and pushing it into the hole.  As the glue sets you have a few seconds to rotate the arm, the normal resting place is on the out side of each window.

C-855 Wipers 7

The last thing I wanted to share with you is a little fix to solve a problem that has been annoying me.  Because the fuel tank on the C-855 is sloped on the under side, not square like the Turbine or U50, the peg on the back of the trucks has to be cut off.  When the loco is on the tracks this causes no problem at all but if you pick up the loco the trucks swing out and hit the ladders.  It also makes it a pain to put back onto the track.

To solve this I have used a piece of plastic sprew from an old kit.  Any thing of a similar size will do.  In the shot below you can see the lug protruding out of the back of the truck with out its peg.

C-855 Truck Swing 1

I simply glued a short section of the plastic onto the top of the lug.  This will still allow the trucks to move freely but wont allow it to swivel out.

C-855 Truck Swing 3

In order to get the truck in without unscrewing the chassis you can simply unscrew the truck and separate it from the geared section.

C-855 Truck Swing 2

Once everything is reassembled the loco is ready for service.

Finished Alco C-855

And just as the C-855 cab units were completed the postman delivered the next bit.  Here is the 3D printed C-855B kit in its raw state. The plastic parts will shortly be going into their cleaning bath and later this week will be off to the painters.

C-855B Kit - Raw

The C-855B brass Additions have been ordered and will also be arriving this week so hopefully I will be able to show a bit more in next weeks post.

A New Pilot for an N Scale EMD DD35

My N Scale kit for Electro Motive Division’s DD35 locomotive uses Bachmann’s massive EMD DDA40X chassis, after some shortening.  But as there’s something not quite right about the pilot on the Bachmann model, in this post I will share with you my designs to add a new body-mounted pilot to the DD35.

All of the real EMD ‘DD’ locomotives use four axle trucks which rotate under the chassis. The pilot, which holds the coupling and multiple unit connections, is part of the main chassis, or body, of the locomotive.  This means that as the locomotive runs around a curve the truck rotates but the pilots remains square to the body.  This is done so the load from the coupling is transferred through the chassis and not through the truck mounting. In this image, from Railpictures taken by Tom Farence, you can see the steps and pilot area are square to the body even though the loco is on the bend.

Bachmann’s model of the DDA40X has the pilot attached to the truck causing it to swing out from under the body on curves, as you can see below in this image of a DD35 between a GP38 and an SD35.

DD35 & Friends 4

This also creates a gap between the steps and the body which is, and looks, un-prototypical.  You can see the steps in the image below disappearing under the shell.

SP DD35 9902 8

So why is the pilot located on the truck? Well Bachmann did it for a good reason.  Because the DDA40X locomotive is so long, without the pilots being on the truck it simply wouldn’t be able to navigate the tight curves, which many of us have on our model railroads, without pulling any connected cars off the track.  Curves on prototypical railroads have a much larger radius and they don’t suffer from this issue. The Bachmann DDA40X can actually traverse some very tight curves but it does look odd doing it.

However there are a few modelers that have the luxury of large minimum radius curves on their layouts and have requested a modification be made to my DD35 kit.  Because I already offer the kit in powered and dummy forms using the same shell I didn’t want to created a whole new shell just for this and, luckily, there is a solution.  The dummy DD35 kit, as pictured below, comes with 3D printed trucks that include a pilot.

DD35 Dummy Pilot

The truck and pilot behave in the same manner as the Bachmann one on the powered chassis and have the same appearance so you can run a powered and dummy unit together.

By extending the pilot section up to meet the underside of the 3D printed dummy chassis or the Bachmann metal chassis, the new pilot can be fixed directly to the body, leaving the trucks free to rotate.

DD35 Dummy Pilot 2

The new pilot section, as pictured below, has been shaped so it will fit the sloping 3D printed dummy chassis or the Bachmann metal chassis, and it has the same mount for a Micro-Trains body mount coupler.

DD35 Dummy Pilot 4

The MU hoses are printed as part of the pilot but can easily be cut off with a craft knife or sanded off if you prefer to fit etched brass ones.

The new pilots are available in two packs.

One pair of N Scale EMD DD35 body mount pilots

Two pairs of N Scale EMD DD35 body mount pilots

Please remember when fitting your N Scale DD35 with a body mounted pilot and coupling it will increase the minimum radius that your locomotive can navigate.  If you are unsure if this will work for you, position your DD35 over your tightest curve and see where the nose of the body swings out to.  If it is outside the sensible condition to be able to couple up to a another car or locomotive then your radius is too small.

I will also be making a similar pilot available for the N Scale EMD DDA40X which I’ll share with you soon.

An Alco C-855 for N Scale

In this weeks post I will share with you the first N Scale 3D printed Alco C-855 and all the accompanied parts.  If you want to read more about the history of this project click here and it will open a new page listing all my posts about it.

This model has been in the pipeline for a few years, so as you can imagine, I was very excited when last week the first test print arrived from Shapeways, and I must say I am very pleased with it.  Below you can see all the parts as Shapeways delivered them.

Alco C-855 First Print 1

At the back is the main shell; all in one piece.  The eight parts in front and to the left are the sand boxes, which fix onto the sides.  Each sand box has a locating peg which fixes into a hole on the side of the shell.  Next to the sand boxes are the crew and control consoles for the cab interior.  Below the two crew is a square plug which acts as a screw mount for holding the fuel tank on.  Next to the crew are the horns, these again have a simple peg which fixes into a hole in the shell.  The fuel tank is next to the horns and the two round parts are the drive shaft extenders.  The final two parts at the bottom are the 3D printed stainless steel chassis extenders.  The plastic parts have been printed in Shapeways’ Frosted Ultra Detail.  Although the Frosted Extreme Detail has a smaller layer thickness than FUD giving an even better finish, this was a test print and I wanted to see how it would come out before going to the best quality.  But even in FUD the details are clear and smooth and I will be very happy with this as an actual model.  Here are some close-ups of some of the detail

Alco C-855 First Print 2 Alco C-855 First Print 3

As normal with parts printed in FUD or FXD they need to be cleaned to remove the waxy residue, so after a rinse of in warm soapy water they spent 24 hours submerged in Goo Gone.

While the parts where getting cleaned I prepared another chassis.  I already had one extended chassis but as I have made some improvements to the chassis extenders I wanted to make up another.  As I have already covered this procedure in a previous post, which can be found here, I will only show the differences today.  I will be making a downloadable PDF available with full instructions soon.

As before I started with a standard Con-Cor U50/Turbine chassis.

Alco C-855 First Print 4

The new  chassis extenders have been tweaked in several places but the most obvious is the introduction of a forward arrow on both parts, this should help with orientation in the chassis.

Alco C-855 First Print 5 Alco C-855 First Print 6

The top section should be done first.  And this simply means removed the section highlighted below.  I used a cutting disc in a Dremel type tool.

Alco C-855 First Print 7The three parts where then glued together.  The key is to make sure the dog leg part of the chassis extender is flush with the underside of the remaining parts.  There should be a small gap at the location where you made the cut.  That way the chassis will be the correct length and it will be easer to keep it square.

Alco C-855 First Print 8

Unlike last time, I also need to make some cuts at the front because the body of the locomotive is narrow below of the cab.  The two wings need to be cut off as shown below.

Alco C-855 First Print 9

Also two notches need to be made.  I will give the sizes of these in the downloadable PDF.  The top notch ended up a bit larger than I had hoped because of the screw hole.  You could simply cut it all off but I want to keep as much weight as possible.

Alco C-855 First Print 10

As I pointed out earlier there is a plastic square plug used to screw in the fuel tank.

Alco C-855 First Print 11

This simply fits into the square hole in the bottom chassis extender.

Alco C-855 First Print 12

It will be held in by the motor and when you screw on the fuel tank, using the same screw from the U50/Turbine fuel tank, it will pull tight.

Alco C-855 First Print 13

With the bottom chassis section it is important to cut it as close to the parts that hang down as possible.  Other wise you may end up with a gap in the chassis frame. Indicated below is the section to be removed.

Alco C-855 First Print 14

Once fully assembled it should look like this.

Alco C-855 First Print 15

My C-855s will be DCC so I have installed a decoder in the space at the rear of the locomotive.

Alco C-855 First Print 16

The next step was to test fit the shell.  In the photo above you can see a square hole at the front of the fuel tank.  Inside the shell is a tapered peg so as the shell slides onto the chassis the shell will spread untill the peg pops into the hole holding it tight.

Alco C-855 First Print 17

The shell is nice fit and once the pegs locate into the fuel tank you can comfortably pick it up by the shell and it wont fall apart.

One of the identifying details on the C-855 is the large sand boxes on the side and because of the locating pegs these can easily be clipped into place.  I have made them a separate part to make it easer to paint the model.  In the photo below they are not glued in place but simple press fitted.

Alco C-855 First Print 18

But as great as the loco now looks there are still lots of parts missing.  And today I took delivery of the first batch of etched brass Additions for this loco.

Alco C-855 First Print 19

As I am going to paint the loco a lot of the parts are not ready to go on yet, plus I only got them today, but to give you and idea of what the finished loco will look like here are some picture with some of the brass Additions loosely fitted.

Alco C-855 First Print 20

Because just about all the brass Additions have mounting holes or slots they should be very easy to install.  The handrails drop into the top of the sand boxes which makes them easy to align.  There are a lot more parts to be added and some, like the ladders, can’t be shown yet as the handrails need to be fixed properly first but as you can see from the image below even the windscreen wipers have mounting holes.  It has swung to its natural hanging position but once glued in, it will line up with the left of the window frame.

Alco C-855 First Print 21

I want to do a few checks to make sure everything is where it should be for all the brass Additions and then the shell will be made available on Shapeways. I think that will happen in the next few days.  The chassis extenders are available now and can be ordered in sets of one, two or three by clicking on the links below.

Set of one C-855 chassis extenders.

Set of two C-855 chassis extenders.

Set of three C-855 chassis extenders.

There is an option to print the chassis extenders in WS&F and FUD which are both cheaper than the stainless steel but you will lose a lot of weight and please note: I have not tested them in these materials.

Although I normally post on a Monday I will do an extra post this week to let you know when the C-855 body and parts are ready as I know several of you are keen to get them.  If you order the chassis extenders now you can add the shell to your order at Shapeways without paying for shipping twice, as long as you do it in good time.  I also have brass Additions in stock, these are £6 GBP each.  Please contact me though contact page or email me if you would like to order some.

The next step, apart from painting and finishing the C-855, is to finish drawing the C-855B.  The chassis will be exactly the same so the extenders will be need for that too.  I will also be drawing a dummy chassis for both locos and will be sharing that with you soon.