Thirdstone - Ep02 - N Gauge Arduino Turntable Project

Since returning to the hobby I have been impressed with the number of layouts which feature turntables.  I want one of those I thought...

An evening of eBay left me winning an auction for a secondhand Peco NB55 turntable and a ridiculously large motor and gearbox.  It put the fear of God into me as it was a 30v monster.  The frame was bent and when I checked the motor's vintage data plate, realised it required a 30V input, so this gearbox must have some ungodly amount of torque.

Total overkill IMHO so the mission was clear:

1. Design and build a roundhouse to integrate with the turntable to store some engines.   
2. Find a suitable high torque low profile geared stepper motor, 
3. Hook it up to an Arduino
4. Write some code
5. Install it on the layout
6. Design and build a roundhouse to integrate with the turntable to store some engines.  

Roundhouse Design

I bought an old Builder Plus BPN24 Double Engine Roundhouse card kit to get some kind of idea of how big a roundhouse I would need and where I could place it on the layout.  I will write up how that build went (spoiler alert: it was a bit of a disaster) and show some photos of the result.  

However, it served its purpose, showing me that the roundhouse would need to be bigger in all dimensions and so I set about designing a new modular roundhouse kit based on the BPN24 design.

The next challenge was how do I plan this roundhouse so I decided on a version with 20 degree separation between tracks.  This angle also determines how close the roundhouse will be to the turntable and I wanted something relatively close.  

I cooked up a base ring in sketchup which would fit tightly around the Peco NB55 shell, this would help me to finalise the position of the turntable relative to the Roundhouse and the engine shed tracks.  

I'm no expert in these things, but the ring was easy to model and with each track coming out at 20 degree that gave me 18 potential exit/entry points.  More than enough for my purposes.  I subsequently found out that prototypical roundhouse are between 10 and 15 degrees.  What does 5 degrees mean between friends anyway... (Foreshadowing)

A late addition to the layout was a long siding.  It was fairly evident during early test sessions that if I want to run long trains (e.g. a 6 x BR Mk1 + a loco) then I need to park these out of the way occasionally.  This moved the roundhouse into the center of the layout a bit more.  

I printed off a few Roundhouse baseplates and discovered that it was not long enough to accommodate my Japanese electrics so this needs to get lengthened.    

The Turntable mechanics

I turned by attention to the turntable itself.  The NB55 shell doesn't move, only the bridge section and having this and the base ring as two separate parts will allow me to clock the turntable for exact alignment.  At least that is the theory.

Looking on AliExpress I found the ubiquitous 28BYJ-48 5v geared stepper motor and ULN2003 driver board combo which seems to be a popular choice for Arduino projects.  This was quite the come down from the industrial sized DC motor which came with the NB55 from eBay.

My go-to 3d modelling software is sketchup which has a free browser version more than sufficient for my humble skills.  I downloaded a model of the stepper motor from Sketchup Warehouse which is a trove of user generated content to make sure that clearances and bolt holes were accounted for and printed out a motor mount.  I was amazed at how easy this was.

I measured the spigot that protrudes from the bottom of the bridge section and modeled a coupling with the correct shape for the stepper motor.  After numerous iterations I managed to get print one which fit through the hole and mated with both bridge and stepper motor drive axle.  

The outside diameter of the coupling might print out slightly oversized but can easily be shaved down to fit. 

The NB55 does not have a flat outer shell, it follows the interior taper of the well at a constant thickness.  I imagine that this is a manufacturing choice which allows the part to be ejected from the injection mould and saves on plastic, but it's a pain in the arse if you want to model a mating plate.  Rather than go through all the hassle of measuring this I just opted for a 2mm thick ring which i can fix to the bottom of the plate .

The observant among you will spot that the ring has flat sides.  This is a byproduct of how computers draw circles.  In sketchup you define how many sides a circle has and it does the rest.  Once printed these sides allow for perfect alignment between ring and motor mount.  

The 3 parts printed out wonderfully on my Anycubic Kobra S1.  God I love this machine.

N Gauge Model Railway - Episode 11 - Can you actually 3D Print an N Gauge Locomotive?

My fleet of N Gauge Locomotives has been slowly growing ever since I began this Coffee Table Layout project but I have been somewhat dissapointed in the affordability of most locos.  

This has meant scouting for old Minitrix, Graham Farish and Lima Locos on eBay which can be picked up at budget prices.  Reliability and running is less than stellar as you can imagine for toy trains which can be around 30 to 40 years old.  

However, being an avid follower Mike and Douglas at the YouTube channel Budget Model Railways and I noticed their affection for the Kato Pocketline locos used on their tiny layouts and was amazed at the effortless slow running of these tiny little marvels.  I subsequently purchased a couple of the very cheap Kato 11-105 powered chassis to experiment with.

Kasugar.Japan

A big shout out goes to eBay seller Kasugar.Japan who furnished me with two chassis for the princely sum of £46.52.  If you are looking for some Kato items or maybe you want those rare JDM Pokemon cards then this is the store for you.  SPOILER ALERT... I enjoyed this experience so much I bought two 11-109 chassis.

Which Kato Chassis do you choose

The main differnce between the two Kato powered chassis is that the 11-105 has two 4 wheel bogies (one powered and driving but both pickup power from the rails) and the 11-109 just has 4 wheels but is all wheel drive and all wheel pickup.

3D Printed Bodies Galore

If you are into your Narrowgage / 009 model railways, you have a plethora of options available for both the Kato 11-105 and Kato 11-109 chassis.  If you want to stick to N Gauge then you will have to do a bit of searching on Cults3D or Thingiverse, but they are out there.

Freestyle Shunters - £1.50 (6 models)

This file is amazing value for mone, I struggle to price up my own downloads and there is always the fear that if you price it too high you end pricing yourself out of the market.  At this price it comes highly recommended.  

I printed off a couple of Model 6, a warship class looking body which the designer recommends for the 11-105 chassis and a couple of model 5 which looks a bit like a class 04.  Printing took an hour and a half and they came out looking great.

Once the tedious task of clipping off the supports was done, Model 6 fit on the chassis perfectly.  Model 5 required some trimming with the dremel and it is a bit of a squeeze but it can be made to fit.  

Sadly when painting I used an untested rattlecan of "white" paint which ended up being gloss and having a really bad reaction to the black primer underneath.  I soldiered on and managed to get a passable attempt at a little BR Green paintjob.  I was only mildly pissed off by the painting disaster because these are 3D printed bodies and I can just reprint them.

 

But what do they run like?

The Kato chassis are very light and they have a tiny motor which is ideal for their intended purpose which is low speed shunting operations and as a result they have very little pulling power.  Anything more than a couple of small wagons and the wheels start to slip.  This can be overcome with the addition of a little weight. 

I added two 5g self adhesive weights to the top of the motor housing and this proved more than enough additional traction to comfortably pull everything in my fleet of wagons and coaches including my Canadian Pacific grain wagons, BR Mk1 Coaches and Siphon G wagons.

 

The incline on my layout was no problem for the tiny little Kato on its own, but it struggled when coupled to anything but the lightest of my wagons.

Other Locomotive Body Options 

Whilst hunting around on Cults 3D I encountered a few options together in my N Gauge Train Stuff collection so you don't have to trawl through pages and pages of train stuff.  I also found quite a few of the odd looking chibi style "Caricature" 009 locomotives which are essentially condensed versions of regular OO/HO loco bodies for the 11-109 chassis type.  Most peculiar. 

On Thingiverse I found the Alsthom 1000 which looks like a fairly authentic reproduction of its prototype.

If you don't have access to a 3D printer Budget Model Railways has you covered one with a range of N Scale Loco Bodies to purchase from their website.

Let me know what you think, and if you have tried printing out your own N Gauge bodies for the Kato chassis please share.

N Gauge Model Railway - Episode 10 - Adding some Low Profile Buildings

It's been a while since I blogged about the N Scale Coffee Table Layout what with the minutae of life having taking center stage.  Whilst there has been a huge amount of progress on the layout I just did not have the motivation to record it.

Cardstock Low Profile Buildings 

Before Christmas I chanced on a joblot of low profile cardboard building kits for a bargain price.  These were all from the scale model buildings N gauge range and are semi photo realistic and obviously taken from photographs of prototypical buildings which have then been photoshopped.  

These were perfect to line the edges of my layout and I developed a technique of cutting out the buildings in layers to add a little depth and visual interest to these already great kits.

Doors and Windows

Using a fresh blade in the trusty craft knife and a steel rule, laboriously cut out each of the windows and doors and put them to one side.  It is important to store these in the same order and orientation in which they were removed for when you want to put the windows back.  

This will leave you with your base layer. 

Add Depth with a Second Layer

Take your base layer and stick this to a second piece of card of a similar thickness using a glue stick.  The buildings are generally small enough that there is enough excess unprinted card to let you do this without needing to break out anymore card stock but following in the footsteps of Michael from the fantastic Chandwell YouTube channel, you can resort to your favourite brand of cereal packet.

Now repeat the exercise cutting out all the window and door apertures.  This will leave you with a double thickness layer.  

Abutments and Protruding Structures

Some of the buildings feature various protruding structures which can be cut out and carefully peeled away from the second layer.  Glue stick is pretty weak stuff so you should have no problem removing these elements.  Stick these to similar thickness card and cut around them.

Glazing Windows

There are a couple of ways you can glaze the windows either by adding a layer of acetate to the whole base layer or by covering the window with cellotape.  I prefer the second method as it does not add a lot of thickness and it is easy to cut through the tape if you are simulating broken glass.  

Using the cellotape technique you could go the extra mile and remove any tape from the mullions and transoms of panelled windows for that matt look.

Using the acetate technique you can simulate larger moder multipanel windows by scoring the acetate gently.  You can then rub these with coloured pencils which will colour in the scratches to form the mullions.  This does tend to warp the acetate creating a sort of bubbled shape to the windows and lots of reflections.  If this is not to your taste then you could just draw the mullions on using a permenant fineliner. 

Edging with Watercolour Pencil

The edges of your building (and window apertures) will now have clean white edges which need to be coloured with paint or my favourite water colour pencils.  This does not need to be a perfect colour match and in fact my dark grey pencil seems to get the most use.

Reconstruction

Any abutments that you created can now be reglued back into their rightful places giving you a solid wall again. 

Rebuilding and Reinforcement

Adding all these extra layers of card that they weren't originally designed into the kit can make them a challenge to keep square when you finally come to fold them together and rebuild the low profile type structures.  I found that adding an interior skeleton of 5mm foamboard was more than enough to produce a rigid structure.  This also gives you a much better surface to attach your roof panels to. 

Replacing Windows and Doors.

You can now refit your windows in their relevant recesses simply fixing them in place with tape.  For particularly deep recesses you can repeat the earlier step adding additional layers to the window apertures to suit your tastes.  If you are gluing these to your backboard as I was then I recommend keeping the final number of layers to a minimum.

Roofs

The roofs included in the kit are the worst aspect.  Typically using just patterned textures as these are likely to be completely unuseable from the prototype photograps, they are a little lack lustre and can either be replaced by better textures from other companies or weathered using the watercolour pencils.

If you are making a silhouette style building the included roof textures are more than acceptable.  however, if you are going more for the low profile look intended by the kit then a stage of artistic weathering is definitely required.

Accessories and lighting

How far down the rabbit hole you go is dependant on your tastes and skill level.  Adding some gutters and drain pipes with strips of card or styrene is an easy way to add that extra layer of detail.

Some of the buildings clearly include security lights and adding these to your building is trivial.  Simply drill through the relevant spot with a small drill bit and fish through an appropriate voltage prewired SMD LED.  These can be affixed with the modellers friend photoreactive resin glue or even white glue.  

Signs and Names

Some of these kit buildings come with signs printed on the buildings.  Whilst the maority are simulating painted on signs some would benefit from being raised from the surface.  You could scan the building sheet into the computer before you start cutting out and reprint the signs onto card to make them a bit more three dimensional.  

If you have access to a 3D Printer you could also model these letterforms and print them out.  This is much easier than it sounds and I have a tried and tested technique for making signs which can be used to great effect here.

Weathering Cardstock Buildings

This is an area of modelling relatively new to me but using a set of cheap artists pastels and watercolour pencils I managed to dirty up some of my buildings.  This is an entirely subjective exercise and is probably best done when you have selected spots on your layout for the buildings to go and then you can weather them into place and achieve a realistic and consistent tonality to your scene. 

Cardstock Buildings at Upper Carrom

Bowerings Animal Feeds - LR-I-009

The Bowerings compsny sign was scanned in and then 3D printed using the technique I menetioned above.  LED lights were added alongside 3D printed drainpipes.

Modern N-Gauge Warehouse - LR-I-011

This building is located on the upward slope of the layout and is a sillhouette building.  It uses the acetate windows technique.

Wood Brothers Ltd - LR-I-001

This buildings roof texture was okay but I needed to heavily weather it to make it look like rusted tin.  The aperture for the sliding door is currently masked with some black card whilst I decide on a suitable interior.

Lion Brewery - LR-I-006

This two storey structure features a loading bay with protective steel posts which I modelled using styrene rod.  Drainpipes were added using the same styrene rod.  The roof is a little lacking in detail and I think could do with a replacement slate tile texture.  Sometimes you are never really happy.

Obligatory Running Video

I recently invested in a tiny action camera measuring no more than 2cm cubed.  After some messing about I managed to get a semi decent bit of footage.  I highly recommend playing this back at half speed.