Alco C-855 R-T-R Build – Part 11 – Lights

This week I’m covering the next part of my step-by-step build of a set of N Scale A-B-A ready-to-run Alco C-855 locomotives, which are almost finished.  You can find part one of the build here.  This step is all about adding the headlights.

These models are going to be DCC, but the same installation will work with DC as well.  The C-855 has a pair of headlights above the cab windows centered in the roof as you can see in the image below.   These lights are very small and although you can get surface mount LED of a similar size its hard to get them to look as rounded as this, or rather as the real thing.

To achieve this effect I have designed the two lamp holes to be printed into the 3D shell but the holes only go halfway into the roof.  For the other half I have designed a larger hole which can only be seen from inside the cab.  In the image below of the upside down shell you can see the larger hole above, or rather below, the windows.  This image was taken before I fitted the windows.

The hole is designed to accept a ‘2mm Lighthouse Warm White LED’ as shown below.  I use these for several reasons. They’re fairly cheep, the spindle part or lighthouse section is small but the rest of the LED is not too small to easily work with.  The warm white light is much closer to the original than the stark white of standard LEDs and the lighthouse design can be used to make a beam of light rather than just an all round glow.

It is important to note that LEDs unlike bulbs only work when the positive and negative wires are connected in the right way.  LED stands for Light Emitting Diode.  A diode, light emitting or not, only allows DC power to pass through it in one direction.  So if the wires are connected the wrong way around, it simply won’t light up.

There are three ways to tell which is the positive terminal on a lighthouse LED.  Firstly, you can see above that one metal leg is longer than the other.  This is the positive leg.  Secondly, looking inside the LED as shown in close up below you can see the split between the two internal parts.  The smaller of the two, shown at the top, is the positive side.

And thirdly, if you have your power source handy such as a 9V battery or 12v DC controller you can touch the LED contacts to the wires and it will light up when connected the right way round.  NOTE: a resistor must be used when doing this otherwise the LED will most likely burn out. This is because the LED will only be able to handle a low amount of amperage and with out a resistor to limit the current the LED, will draw all the amperage the power source has available.  The resistor can be on either the positive or negative side, as long as the power passes through it.  I will show you how I place mine shortly.

Because the LED omits light from all sides it’s important to ensure we only get light where we want it.  If you have one of the older Con Cor Gas Turbines, which chassis we are using for this build, you may remember that when the headlight is on, the whole cab illuminates.  What doesn’t help is the FUD or rather ‘Fine Detail Plastic’ material Shapeways use is porous to light.  However these shells have been primed and painted which gives a good block to the light showing through but just to make sure I always paint the inside of the cabs with a matt black.

I doesn’t have to be a pretty job, but I like it to be thick.  I also make sure I get some in the hole where the LED fits, this bit doesn’t want to be too thick otherwise the LED won’t fit.  I used to paint the LED with the exception of the top of the lighthouse to prevent unwanted light but I now have a better method  I will share with you in a minute.

The legs on the LED need to be cut down so the LED fits into the cab roof area.  Make sure you leave enough to solder wires to.  At this point the first way of identifying the positive side of the LED is no longer possible, unless you cut one longer than the other.

The LED wont go all the way into the hole because half way in the big hole becomes the two smaller headlight holes.

To stop the light filling the cab I now wrap the LED in heat shrink.  I use a tube which is roughly the same size as the box part of the LED and cut it so it will cover everything except the tip of the LED that goes into the hole.  If this part has heat shrink on it will not fit into the hole.

The box is actual bigger than it looks and the heat shrink tube is a tight fit but with some effort can be forced over the LED.

Then using my soldering iron I can shrink the tube around the LED.

The only part of the LED which can’t be covered like this is the rear of the box between the wires.  So I simply paint that with black matt paint.  A pair of tweezers are an easy way to hold the LED while painting as they naturally clamp it.

Once the paint is dry, 15 minutes with the acrylic paint I use, the LED can be test fitted.  Ideally the heat shrink should go all the way to the edge of the hole to prevent any light showing through.

For the resistor I have used a  small 1k ohm.  Being only a 4mm long it will be easy to fit into the space in the top of the chassis.  I cover the electrical connections to prevent them from touching the chassis with another piece of heat shrink.

I have soldered the white wire from the decoder to the resistor, the white wire is the front light negative.  The blue is the common positive.

The heat shrink is then pushed over the resistor, shrunk on with the soldering iron and it’s all tucked into the space in front of the decoder.

The wires can then be soldered to the LED.  Don’t forget to check which is the positive connection first.  I also used two small pieces of heat shrink to cover the joints.

With all the connections made and covered, I did quick test on the power to make sure everything worked.

Because the shell may need to be removed for maintenance at a latter date I don’t glue the LED into the cab roof.  I use a bit of black tack to hold it in place.  This should hold it firm but it can be peeled off at any point.  Black Tack is a high strength adhesive putty designed for photographers. I find it fantastic at holding decoders and other bits in place.

The head lights are now ready for the proper test and as you can see they look really good.

If your running on DC then you still need to use the resistor.  The wires coming from the LED, via the resistor, simply need to be connected to the chassis power points.  One to the left hand side and one to the right.  In the image below, taken from part 5 about fitting DCC decoders, you can see the two contact point which will also be used to connect the motor to.

Because the LED will only light up when power is applied in the correct direction the LED should only light up when the chassis is running forwards, on DC power.  If it lights up when running backwards the wires need to be reversed.

These models have not been designed with a rear headlight, mainly because I intended mine to run as an A-B-A set.  Therefore the C-855B has no lighting.

As this post turned out to be a bit longer than anticipated, I will leave the detail parts such as the fuel tank and etched details, for next week’s post.

Alco C-855 R-T-R Build – Part 10 – Window Glazing & Wipers

This week I’m covering the next part of my step-by-step build of a set of N Scale A-B-A ready-to-run Alco C-855 locomotives.  You can find part one of the build here.  This step is window glazing and fitting window wipers.

Now that the decals have all been applied, with the exception of the number boards, I can sort out the window glazing.

This wasn’t done sooner as some of the paint needed to be finished by hand, such as the red lining over the front wwindows. I do this by hand as there are four holes for the windscreen wipers and it’s easier to paint the stripe than cover the holes with a decal and try to find them again.

If the glazing was fitted first there would be a risk of getting paint on it.

The glazing, only required for the C-855 A units, consists of 5 parts; a center section which covers the four forward windows, two side sections for the pairs of side windows and two door sections for the doors at the rear of the cab.  I cut my window glass from clear acrylic sheet.

The main section is 18mm long and 6mm deep.  The cut out at the bottom is 10.5mm long by 1mm deep; this is to avoid the chassis.  The side window sections are 6.5mm wide by 5.5mm deep. They are shown in the wrong orientation in the photo and fit into the cab turned by 90°.  The door sections are 3mm wide by 4.5mm deep.  These sizes are rough but allow the window hole to be totally covered giving enough space all around to fix the glazing in.  So if your slightly off it’s okay.

I tend to start with the main window section. As with anything like this I always do a test fit first.  With the shell resting so the nose is at the bottom I’m able to drop the window in using a pair of tweezers.  If it’s a good fit I take it out, but if it’s not a good fit I trim it down where needed and try again.

To fix the glazing I use a very small amount of superglue.  The reason I only want to use a tiny amount is because of the reaction superglue fumes have on fingerprints.  As much as I try not to I still get fingerprints all over the glazing, then, if a lot of superglue is used, the fumes stick to the prints and they show up on the glazing, turning it hazy.  So to prevent this I put a drop of glue onto a piece of card; something glossy is great so the superglue won’t soak in.

Then using a pin I put a dot of superglue in each corner of the windows, and as this is a set of four windows I also put one above and below the middle.  Then using the tweezers I place the glazing back in.  As the glazing and shell are made from acrylic and so is superglue they all bond quickly together with no fumes when the glazing drops into place.  In the picture below you can see the front glazing stuck in place.

This is then repeated for the side windows and rear doors.  As long as the glazing isn’t any bigger than the given dimensions it will not interfere with the fitting of the cabs and crew.  Once fitted the glazing gives a much better look to the cabs.

Now I can fit the windscreen wipers.  They are located in the etched brass fret on the right hand side, one for each of the front windows.

In the picture below I have cut out the right hand pair.  (Right hand as you are looking at the loco, not from the driver’s perspective).

About 1mm in from the left hand side of the arm is a half etch section on the rear of the etch; this is where the wiper arm needs to be bent in order to attach it to the shell.  I use a flat pair of tweezers to hold the wiper and push the arm over with my finger.  Because of the half etch the arm will bend in the right place.

Now I do a test fit.  The holes on the cab for the wipers are the right size and they should fit well but it is possible that the holes have filled with paint. If that’s the case a 0.5mm drill can be used to reopen the hole.

I use a pin vice for small drills like this.

With the holes open the arms can be test fitted; you can see the first arm test fitted below.

Once you are happy then it can be fixed in.  Again I use superglue for this but not applied directly to the model.  I put a fresh drop on to my piece of card and using the tweezers lightly dip the bent arm into the superglue then put it back into the hole.  You have a few seconds to position the arm where you want it before it sticks.  The main windows the engineers look out from are the deeper outer windows.

The C-855 shells are almost finished.  They still need the sand boxes adding, as well as the handrails, crew and a few other details such as the lights which I know a few readers are waiting to see how to do. This will all be covered in next week’s post.

Alco C-855 R-T-R Build – Part 9 – Decals

This week I’m covering the next part of my step-by-step build of a set of N Scale A-B-A ready-to-run Alco C-855 locomotives.  You can find part one of the build here.  This step is decals and how to apply them.

There are lots of different ways to apply decals and I’m sure some are easier than others but I’ve found a system that works for me.  I originally used to print my own decals; this has the advantage that you can get whatever you want, with the exception of white.  You need an Alps printer, or something similar for white.  But it also comes with a few disadvantages. I found that with homemade decals the color looks great on the sheet, with the backing paper behind it, but as soon as it’s applied to the model the color of the model affects the color of the decal.  This is because the layer of color on the decal is not that thick.  For example red letters or lining on Union Pacific Harbor Mist Gray went very dark, but on the Armor Yellow stays bright.  If the decal crossed the two colors it looked rather odd.  So now I tend to use specifically made decals from Microscale or Circus City.  Their color layer is thick and the decal can be placed onto anything without color change.  Also they do seem to stick well.

So how do I do it?

The tools I use are a craft knife, always with a new blade, a modeling paint brush, a pair of tweezers, a metal rule, a foil tray with some water, a sheet of paper towel, Micro Set solution and Matt Cote.

I always use a new blade because I’ll be making some small precise cuts and I want the decal paper to cut not tear.  A blunt blade may cause the decal to move slighty on the backing paper rather than slicing through it or it may cause the backing paper to wrinkle, destroying the decal.

The foil container of water is because these are wet slide decals so we need the water to separate the decal from the backing.

And the paper towel is to absorb the excess water; if there’s excess water on the decal it won’t stick. I also have a scrap of paper towel, about the size of my thumb, which has been folded a few times to give a crisp edge and is also dampened.  I’ll explain what this is for later.

Micro Set and Micro Sol are both products from Microscale for setting and fixing the decals to the model. Micro Set is a setting solution to help the decal adhere to the model.  Micro Sol is a decal softener which allows decals to be pushed onto tricky shaped areas.

Matt Cote is made by Humbrol and is a varnish that goes on clear and dries clear. It dries to a smooth, low-sheen, matt finish.

The decals are printed onto a clear film which is stuck onto a backing sheet and they need to be cut out.

Large decals can simply be cut out using the knife or even a pair of scissors but small items such as loco numbers will certainly require the knife. Strips such as the lining need to be cut out in a certain way.  If you simply run the knife around the decal there’s a chance you will cut the decal itself and if you cut the ends first it will curl up as you cut it out.  So, being right-handed, I place the rule so the edge is just to the right of the decal and run the knife down the side, starting above and finishing below the decal.

I then place the rule just to the left of the decal and cut the other side.  Because the ends had not been cut the decal doesn’t curl up.  If there is some of the clear film between the cut and the decal that is okay; if you are too close you could cut the part you want.

The ends of the decal can now be cut and the strip can be removed ready for use.

I always test fit the decals to be sure. The vents or grills on the C-855 will be blackened so I’m not going to run the decal over them. Also running the decal over the vents will hide the great detail.  Any areas such as this which do want the red strip I will touch in with paint later.

Once I’m happy with the piece I want to apply I dip it in the water for a few seconds and place it on the paper towel. I then use the brush to lightly wet the areas where the decal will be going with Micro Set.  At this stage the choice of priming the models before applying the paint pays off because of the material used to 3D print the shells can be porous and the Micro Set would sink in too fast.  But with a primer and gloss finish the decal has a smooth surface to adhere to.  Matt finish paint is coarser than gloss which also gives problems when getting decals to stick.

Once about four minutes have passed I pick up the decal carefully and push the decal on top of the backing paper and it starts to slide off.  Then, using the tweezers to grip the backing paper, making sure I don’t grab the decal, I position one end, hold it in place with the brush and pull the decal off the paper.  In an ideal world the decal lands exactly where I want it, but normally it doesn’t, so using the brush, I position it correctly.  The Micro Set evaporates fairly quickly and as it does the decal fixes to the model.  The glue which held it to the paper was loosened by the water and then reactivated by the Micro Set.  If I’m happy with the position I use the small thumb sized, slighty damp, piece of paper towel to press the decal down.  This gets rid of any air trapped behind the decal and ensures a good, flat fixing.  It’s damp to make it maleable and soft.  If I’m not happy with the position I can use the brush to put some more Micro Set onto the decal and it will start to slide again.

As well as the lining, the words and numbers on the model are important.  Under the cab will be the words ‘Dependable Transportation’.  These are on Microscale sheet 11-92.

This is a small decal and hard to see up close but I’ve simply cut out the rectangle leaving a bit of space from the edge of the lettering.

I do a quick test fit.

Then dunk the decal in the water and wet the area under the window with Micro Set.

Then, when it’s ready, I slide the decal in place.

Once pressed down the clear film around the letters disappears.  I then do the other decals such as the big Union Pacific, loco numbers and bottom red stripe.  This stripe also runs around the sand boxes but it’s easier to do the main body before they are fitted.

One of the main features of this iconic locomotive is its nose and being a UP loco, UP like to let you know it’s one of theirs.

There are areas which still need a few decals, such as above the cab windows, but these will be touched in later once the windows and details have been added.

Lastly, the decals need to be sealed otherwise they could be rubbed off by handling the locomotive. You can use an airbrush or spray can and coat the locomotive in a laquer.  I’ll be spraying the locomotive with Testors Dullcote when finished, but for now I’ll be covering the decals with a layer of Matt Cote applied by brush.  The Matt Cote is fairly thick and it’s also a solvent which softens decals so I always cover the them in one pass.  I need to be sure before putting this on because once a decal is coated in this it won’t come off without being cut off.

With all the primary decals applied I can now add the windows and most of the fine details, such as the windscreen wipers, which I’ll cover in next week’s post.

Alco C-855 R-T-R Build – Part 3.5 – Chassis Prep Extra

This week I have an extra post to slip into my step-by-step build of an N Scale A-B-A Ready-To-Run set of Alco C-855 locomotives.  Back in July I posted part 3 which covered the chassis preparation procedure, you can find it here.  However I missed something so in this post I’ll cover what it was and how to do it.  My apologies to anybody who has been following this build along with me.  I will update part 3 which will make this post redundant but for now here it is.

You may have noticed I regularly recommend test fitting things as you go and I should take my own advice.  The chassis below has been prepped to fit into a C-855 A unit and at the cab end you can see how the top chassis section has been notched to fit into the narrow nose.

But the lower section doesn’t fit all the way in and a test fit before I assembled the chassis would have told me that.  In the picture below I’ve removed the lower chassis section and placed it into the shell.  As you can see the inside corners of the nose clip the shell.

However this is easily fixed by cutting two notches in the chassis section as marked below.  Each notch is 3.5mm (0.1377“) wide by 2mm (0.0787“) deep leaving a nose of about 6mm (0.2362″) wide.

I cut these out using my Dremel tool and cutting disc.

The bottom chassis section now fits into the shell.

This extra notching is not required for the C-855B chassis as it doesn’t have a nose.  Next, as I have disassembled and resembled the chassis, I’ll test them for running smoothness and any binding in the drive shafts. Then it’s on to the shells which will be in a later post.

Alco C-855 R-T-R Build – Part 5 – Fitting DCC Decoders

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 fitting DCC decoders to the modified chassis.  You can find part one of the build here.

Although this post is aimed at DCC installation the first part is also relevant to DC operators.

The chassis, as you can see below, is held together by vertical bolts which clamp the top and bottom sections together.  But the bolts also do more than that.  Instead of a nut on the bottom the bolts screw into the plates which hold in the trucks, and in turn convey the power into the chassis.  The bolts nearest the front of the picture and on the left hand side of the locomotive connect the left power pickup to the top chassis section.  The bolts furthest away and on the right hand side are isolated in plastic sleeves and connect the right power pick up to the lower chassis section.

When these models were new they had a grain-of-wheat bulb connected to the front bolts which was used for the headlight, and illuminated the cab!  But we can now use these as power connections for the DCC decoder.  The original bulb had a diode attached so it wouldn’t operate in reverse.  Con Cor soldered the bulb wire to a tab plate under the bolt head and twisted the stiff diode wire under the other.  As I want to ensure good contact between the chassis and decoder I’ve made another solder tab for the other bolt as can see below.   I made it from an old axle wiper taken from a scrapped locomotive.  The decoder, also shown below, is an N scale sized chip from Gaugemaster but any DCC decoder will work as long as it fits.

Now, before we start with the decoder some electrical bridges need to be added.  This is the part which also needs to be done for DC operation.  In the picture below you can see I’ve linked the two right hand side bots together as well as the left.  This is because where the chassis has been cut and extended the new glued joints can form an isolating barrier.  So if the decoder was simply connected to the two front bolts it wouldn’t receive any power from the rear truck.

The center sections will also be isolated and as the motor used to collect power by having the contact simply touching the chassis, it’ll no longer work.  So the motor wires I’m about to install for DCC will also need to be connected for DC but just back to the solder tabs.

For the DCC decoder the red and black wires are cut short and soldered directly to the solder tabs. They should now be linked to both sets of trucks.

The chip can then be folded in and secured with Kapton tape.  Kapton tape is ideal as it’s isolating, thin, strong and designed to withstand heat in electrical situations.

The gray wire is the bottom motor feed and runs outside the chassis and is soldered onto the bottom motor tab.

There is a wire channel printed into the chassis extension for this wire as you can see below.  This wire, once fitted can be covered in a piece of Kapton tape or glued in.

The orange wire runs halfway down the other side and connects to the top motor tab. It could go through the hole in the top but I like to do it this way.  The blue and white wire are for the headlight so stay at the front.  If you wanted to add a rear light the yellow and another blue would need to be run to the back but as these will run in an A-B-A consist the rear light is not necessary.  With all the wires connected, except for the head light wires which I’m going to cover in a later post, they can now be fixed down.

Again I used Kapton tape to hold the wires down.  It’s important to position the wires in the middle of the chassis as they run from one end to the other as the shell has feet which sit on top of the chassis.  But there’s a gap in the middle of the foot to allow the wires to pass.  The two strips of Kapton tape are where the feet sit.

The chassis is now ready for DCC testing.

The next step is to fit the shell and for that I have to finish painting it which I’ll cover in a later post.


Alco C-855 R-T-R Build – Part 4 – Chassis Assembly

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 assembling the chassis.  You can find part one of the build here.

Now the chassis sections have been extended it’s time to reassemble all the parts.  And for this build I’m also going to upgrade all the motors to newer Kato drives.  In the picture below you can see all the original parts plus the new Kato motor in the top left-hand side.

For this post I’m going to assemble the second chassis which you may remember from last week is for the B unit but the process is exactly the same for all three locos.  To start with I add the black plastic isolators into the pockets on the underside of the lower chassis section followed by the metal truck fixing.  Both are held in place by a countersunk screw, the shortest ones, which only pass through the lower chassis section.

Next, and this in an important one not to miss, the first new 3D printed part needs to be added.  It’s the small square screw fixing which holds on the fuel tank.  In the original the lower chassis has a threaded hole to receive the screw but as this section has been replaced by the stainless steel chassis extender a new fixing is required.  Threading the hole would require more work and it’s much easier to drop in this plastic part.

The square part simply presses into the square hole.

It will stay in place by friction and once the motor is fitted it can’t fall out.

The motor sits in a plastic cradle; this is to isolate it from the metal chassis.

The cradle has a peg on the bottom which fits into the hole in the chassis to ensure it’s in the right way around.

Next comes the motor.  Although I’ll cover this here I’ve written about this procedure before in a bit more depth which you can find here.  The new Kato motor doesn’t come with any gears on the drive shafts so the original ones will need to be removed from the old motor.

This is actually fairly easy to do.  I use a pair of needle nose tweezers, simply grip the shaft behind the gear and push it off.  Just don’t do it too fast or the gear will ping off behind the work bench!

To fit the gears to the new motor simply press them on with your fingers.  They want to go on so far that the shaft pokes out the other side but make sure the gears are not tight to the motor body and the motor can spin freely.

The next 3D printed parts are the drive shaft extenders.  These are toothed parts which fit inside the existing cup gears making them longer.

I used to glue these in but as my fellow modeller Mike Musick pointed out, they work better when left free with a bit of movement.  You can read Mike’s views on this here.

Also, as you may remember from last week’s post, Con Cor have over the years made a few changes to their chassis and one of those changes was to this cup gear.  The very first design had a different number of teeth in the cup.  This means the extender won’t fit.  But don’t panic, firstly these early chassis are now getting rather rare but if you are using one for you C-855 build you can get drive shaft extenders which will fit here.

The motor is now ready to be added into the chassis.  But first it’s very important to make sure the new drive shafts spin freely without any rubbing on the chassis. Across all the Con Cor chassis I’ve converted I’ve noticed that the drive shaft length varies; I have no idea why.  I’ve supplied the drive shaft extender for the more common shorter lengths I’ve come across.  This does mean that if you have longer ones the drive shaft will now bind against the chassis extender.  To overcome this pop the drive shaft back out and file down the 3D printed part on the cup side.  Running the part up and down a file will do this.  But be sure to make the reduction even.  I would also recommend doing a bit at a time and test fitting as you go as you don’t want to make them too short.  If you do you can get more here.  Once everything is good this would be a good time to add a tiny amount of light oil to each bearing, just a drop.

There may also be one more issue to resolve if you’re using the latest Rail Barron version of the chassis.  Con Cor updated the motor casing and added the curved notches you can see in the picture below.  And therefore added some material into the motor cradle so it’s a nice tight fit.  But this means the Kato motor won’t fit!  It fits fine in all the others.

These extra plastic parts need to be removed to get the new Kato motor in and I find the best way to do it is with a with a small burr bit in a Dremmel style tool.

All four corners will need to be removed to allow the new motor to fit.

Also, and this apples to all the cradles, a shim needs to be added to the base of the cradle as the new Kato motor is slightly shorter than the Con Cor one.  Before you glue the shim in a test fit is required because if it’s too thick it will create uplift on the cup gears which will be noisy and wear out the motor.

The motor fits in to the cradle with the motor contacts at the end with the larger hole.

You’ll need to lift the drive shafts in order to fit the motor in.

Once fitted and you’re happy that everything spins freely, and the motor turns both drive shafts, it’s time to add the rest of the chassis.  There are two plastic separators which also hold down the drive shafts, these get fitted next.

Then the top section of the chassis can be fitted and the other screws fitted between the top section and the metal truck fixing. The longest screws with a plastic insulator are used on the right hand side.  The medium screws are used on the left without insulators.

With the trucks installed the extended chassis should look like this.

At this point, using wires from a DC controller, I do a basic test to make sure everything runs well.  If it’s noisy, won’t run, or sounds like it’s struggling, STOP,  there are a few things to check.

  • Can you easily turn the motor with your finger?
  • Are the drive shafts seated properly?
  • Check the drive shafts are not too long and binding on the chassis.
  • Check the gears on the motor have been pushed on far enough but not too far.
  • Is the shim under the motor too thick forcing the gears up into the cup gears?
  • Are the gear towers in the trucks jammed?

Hopefully everything runs okay with all the checks done and any issues corrected.

The next step is to wire up the chassis, I will be doing this for DCC but I’ll cover DC as well and it will all be in the next post on this project.