DOUGAL
by James
Background
Dougal is a small 0.4.0 wing tank
built by Andrew Barclay in 1946. It formerly worked at the Provan gasworks in
Glasgow and now resides on the Welshpool and Llanfair railway (W&L).
Compared to other locomotives on the railway it is tiny but this doesn’t
prevent it from hauling occasional passenger and freight trains during special
event. Indeed, a trip behind Dougal is always a highlight of the gala for me.
From the balcony of the Zillertalbahn coaches, the chimney is actually below
you resulting in an interesting trip when running bunker first!
The model
Having grown up in Llanfair
Caereinion, I have a great interest in all things W&L and have always
wanted a modell of Dougal but as far as I’m aware none has ever been
commercially produced in 16mm scale. I’m a member of the Cardiff Model
Engineering Society (CMES) which has a small garden railway group. We meet
every week and either work on the club track or convene at master builder Tony Bird’s
house where we all have individual projects. Since I joined I haven’t had a project as
such but after having a few discussions with Tony and others, it seemed that a
model of Dougal would be an ideal project.
A few options were looked at.
Scratchbuilding the whole thing was a possibility and with Tony’s help,
eminently achievable but as we only meet for 2 hours a week it would take a
long time to complete. I then looked at using a steam motor and building the
model around that but the work involved in constructing the rest of the loco
was time consuming and being impatient I wanted something I could be running
relatively quickly.
So, my thoughts turned to using a
commercially available model as a basis. I discovered that the Accucraft Ruby
had almost the same wheelbase and wheel diameter as Dougal and being relatively
cheap appeared to be just what I wanted. I didn’t realise however, how hard it
was to get hold of a reasonably priced Ruby. No retailers in the UK seemed to
stock Ruby’s and very few came up secondhand
and tended to go for more than I was willing to pay. So I looked abroad
and discovered that I could buy a Ruby from the USA including postage for less
than they were lifted in the UK. The new Ruby’s have the added bonus of being
fitted with the larger Edrig style cylinders resulting in much improved
performance.
One of these was duly purchased
and arrived after a couple of weeks. I soon had it unwrapped and running on
blocks in my garage. Everything seemed ok so I headed outside for a test run on
my line. Being manually controlled the run wasn’t very relaxing but it showed
that Ruby was free steaming, powerful and easily capable of hauling the sort of trains that Dougal runs with
in real life.
I also took it down to the CMES track at Heath Park during a public open day where it ran impeccably with running times nudging 30mins and the equivalent of a full length W&L train on the drawbar. Satisfied that it worked ok, I started to dismantle the loco to get a better feel for its size.
The Build
I had prepared a number of
drawings a varying scales in an effort to get the right look with the finished
model. At 16mm scale the Ruby wheelbase was slightly too long so rather than
have a larger wheelbase and scale body which to my eyes looked wrong, I scaled
the whole drawing up to 18mm scale to suit the wheelbase. This made the whole
machine larger but not so large that it looked out of proportion. This wasn’t
intended to be a scale model as such, but getting the proportions right was
important.
The next step was a simple
cardboard mockup of the tanks and bunker to 18mm scale. To me this looked right
and when positioned next to my Accucraft Countess, it still looked suitably
diminutive. So, enthused that I had a plan, I headed down to Tony’s house one
evening.
Comparing the chassis to the
drawing, it was clear that a few things would have to be either moved or
replaced. The gas tank was way too tall and the regulator fixing was far too
large. The boiler design was most unfortunate however. It had two take offs,
one for filling and the other for the safety valve, both of these being
disguised by large domes. Unfortunately neither of these domes matched the
location of those on Dougal and I had resigned myself to the fact that this was
something I would have to live with. Tony however, having studied loco and drawing
for a while, proclaimed, “we’ll just make a new boiler, it won’t take too long”.
Having no experience of this, I obviously hadn’t planned anything on this scale
but Tony assured me that it would be far easier to build a new boiler than try
to modify the turreted take offs on Ruby’s boiler. So it was decided this was the
way forward and dismantling of the loco began in earnest.
The loco was completely taken
apart until just the frames and wheels remained. Dougal is a very simple
looking locomotive, with everything fixed top the same running plate. It is
also all at the same level so the first thing to do was to construct this. A
piece of steel was found and marked out to match the width of the cylinders and
the length of the drawing. The actual
Ruby frames are slightly too long but removing a short piece of these from the
rear would have no structural effect so the frames will eventually be
shortened.
On Ruby the steam pipe runs from
the regulator to the cylinders underneath the boiler, there is no superheating.
The piston reversing valve is situated directly below the steam pipe which
restricts the amount of adjustment that can be made to the position of either of
these. The centre section of the footplate was removed to allow for the steam
pipe and reversing rod to remain in place.
A pair of frame spacers were
machined from steel, tapped to accept the screws through the frame and were
fitted front and back. This sounds simple but it was the first time I’d used a
lathe since school and therefore took a lot longer to produce than I expected.
It’s a tremendous feeling to actually produce something though so it was
definitely worth the effort. The Ruby frames were slightly too long compared to
the drawing of Dougal so about 10mm was cut off the rear of the frames and brad
new buffer beams fitted front and back. Accucraft choppers were fitted by being
screwed straight through the buffer beams into the frame spacers.
As Ruby is a bar frame loco, the
chassis is very see through compared to the chassis on Dougal. Therefore, the
final job to do on the chassis was to fit a couple of pieces of sheet steel at
the rear to represent the frames of the loco. Once this was done, the chassis
was essentially finished.
Whilst this work was going on, I
bought the equipment necessary to fit the loco with radio control. Two micro
servos, a mini receiver and AAA batteries were purchased and these were trial
fitted to ensure that radio controlling is feasible. Luckily Dougal has two
water tanks and two bunkers, essentially four boxes in which to put things like
servos and the like so fitting them in shouldn’t be a problem and they should
also be pretty invisible.
With the work on the chassis
finished, attention turned to the boiler. Building a boiler is something I have
never done before, in fact I hadn’t even contemplated it so I was completely in
Tony’s hands at this stage. A design was drawn up that provided as much water
space as possible in order to prolong the running time. One interesting result
of this is that the loco will have a steam dome where the regulator take off
will be, exactly like a full size loco, it looks complicated but I’m assured it
will work! A piece of copper pipe of suitable dimensions was found along with a
smaller piece of copper pipe for the flue.
The first job was to cut the
boiler to the right length and then square the ends off. So it was onto the
lathe again to get this done. Next, the tubeplates were formed. This was done
using copper sheet, cut into a circle and then bashed into the correct shape
around a wooden former, the copper having to be annealed a few times to get the
correct shape. Again, it sounds pretty simple but cutting two circles of
copper, making the former then shaping the metal took the best part of three
weeks.
Here's a shot of Dougal with the sloping water tanks. Not sure when this was exactly but I would guess around 1993ish? I think it looks better with the square tanks.