Back in the summer of 2007 Aster UK distributor Andrew
Pullen announced the new British outline model from Aster. Much to most
people’s delight it was to be a 9F – that was great news for those of us
who had been pleading with Andrew for one of these for some time.
After the railway nationalisation in Britain in 1948 and as
a result of the publication of the exchange trials conducted shortly
thereafter, the need for a new large freight engine was announced. It was
shown that what was required was a design with greater boiler capacity
than previously available capable of sustaining higher speeds both on the
level and in hill climbing. For some time the team doing the studies
recommended that the new loco should be a 2-8-2 but, after much argument
between Robert Riddles, Chief Mechanical Engineer of the Railway Executive
and E. S. Cox, Chief Officer, Motive Power, a volte-face resulted in a
2-10-0 being chosen in 1951. The subsequent release of 251 of these fine
locomotives starting in late December 1953, was to prove the worth of the
studies. Much as these two gentlemen led the planning phase, the
development and production of these locos was attributable to others in
the engineering team. The 9F’s success was largely due to the locomotive
design staff in Derby under the leadership of Frank Carrier. The detail
design work however was conducted in several of the surviving design
centres of the old constituent companies of British Railways and was
therefore a national team effort and something of a magnum opus for
British steam locomotive design.
Hence it is very gratifying that Aster should have made
such a beautiful job of scaling their new model. The initial photographs
of the prototype released showed that it was to be a model of 92220
Evening Star in its fully lined-out Brunswick Green splendour as seen at
the National Railway Museum in York. However, Andrew was quick to announce
that there would also be an alternative black version modelled on 92214
which is, of course, another preserved loco whose restoration was
completed at the Midland Railway Centre at Butterley in Derbyshire. Both
versions being products from Swindon Works.
As more photographs were released it became apparent that
we were about see another step forward in both technical detail and
fidelity to the original design. Firstly, there were to be piston valves
replacing the usual slide valves, a first for Aster. Next there would be
cylinder drain cocks only previously seen on a few foreign models at the
more expensive end of the Aster market but pretty well essential for an
engine fitted with piston valves. It also became obvious from the
photographs, and later the drawings, that the fully reversible valve gear
was to be a close copy of the full sized mechanism of the wheel type
mounted in the correct plane.
In most other respects the engine represents a further
development of the well tried and tested design and construction. It
includes a very rigid, cross-braced and fully sprung chassis with
flangeless centre drivers as per the original and is fitted with an axle
driven pump. Onto this is mounted a large C type boiler with blower and
superheater of the usual design. Both of the models to be produced have a
double chimney as fitted to their big brothers when built at Swindon. A
first look at the design of the front end of the model suggests the
possibility of a single chimney version and this has now been produced by
Aster/Accucraft as a later batch. The boiler casing is beautifully
detailed with all the ‘bells & whistles’ showing and includes a dummy
representation of all the external boiler mountings as far as I can see.
The cab is glazed too, another first for a British outline Aster.
The tender used for the early batch of Aster locos is the
BR 1G type as designed for use on the Western Region of BR. Full sized, it
had a capacity of 7 tons of coal and 5000 gallons of water. The second
batch tender is to the BR1C design of the high-sided type as produced in
Crewe for the London Midland Region.
Other than the features mentioned above there are few
variations between the locos. But as usual if you want to build a
representation of your particular favourite you must obtain a good photo
and work from that. Good sources of both photos and history can be found
in two specially recommended volumes – Richard Derry’s ‘The Book of the 9F
2-10-0’ published by Irwell Press and the out of print ‘The British
Railways Standard 9F 2-10-0’ by Philip Atkins also from Irwell Press.
It became immediately apparent that a kit with this level
of sophistication and complexity was going to need very careful study of
the drawings and rigidly sticking to the recommended build sequence. What
follows are my notes taken from what I discovered during the build and
where considered necessary, to offer tips on construction as I have done
before. I do not intend to suggest in any way excessive difficulty but
rather the need to remember how to eat an elephant – one mouthful at a
There are no special tools or equipment necessary for the
construction of this kit. Reference to earlier articles that I have
written for the Journal and elsewhere will show what I use. Once again I
do recommend the acquisition of a set of three hand broaches as used by
the clock makers. These are used to ease tight holes usually caused by an
excess of paint. In addition, I recommend that builders will find benefit
from having taper taps in M1.4, 1.7 and 2 mm size again to clear threads
that may have been partially blocked with paint or swarf.
The kit arrives in the usual very strong box with most
components separately boxed and packed in tissue paper and bubble wrap.
Care should be taken to only unpack those components needed for the task
to be undertaken. Check the parts against the inventory provided and the
excellent drawings. Section 1 builds the main chassis and is fairly
straightforward. Note that the stars shown on 4 bolt holes indicate the
use of countersinks and are on the outer faces of the frames. Build the
frames on a thick glass plate and test regularly to ensure that there is
no transverse or longitudinal rock. If there is you must adjust the
assembly to bring the chassis true, hence ensuring that the axleboxes will
not bind. Remember to use a fine file to finish the running surface of the
cross heads to ensure smooth contact with the slide bars. I’m of the
opinion that access to the cylinder drain cock operating lever locking set
screw is impossible after the boiler is fitted. Care should be taken to
make sure that the thread UNDER the operating levers is used for the grub
screws. They are then easily reached with the loco inverted. I recommend
that Loctite 222 or stronger be used.
Section 2 installs the wheels, axles and the axleboxes.
Before fitting each however, the counter-weights have to be fitted to the
wheels. It is important to examine these weights carefully as the outer
ones are in a package with yellow marking and the blue ones are the inners
and are thicker than the outer. If you put them on the outside you will
find that the weights foul the rods! The Inners have countersinks on their
inner faces to recess the heads of the long screws. The screws which do
not have countersink heads retain the weights in place and the screw tails
are flush with the weights’ outer faces. Hence they are only just long
enough and if you don’t have the countersink on the right way around the
bolts will appear to be too short!
Before you fit any of the wheel sets first install the two
Pt. 16 weights to the chassis as you will be unable to fit them with the
wheels in place. Also, note that the dummy brakes are not fitted until
Section 3 when the axle pump is assembled and fitted. Here I usually make
a change; I fit nitrile balls to the axle pump clacks as I find these
never let me down, something that I cannot say about the s/s balls
provided in the kit. Though it should be added that later balls delivered
in kits seem to be better. The option is yours.
In Section 4 the valve gear is assembled and I would first
recommend that you get your taper taps out and run through all of the
threads to make sure they are not too tight when pins and screws are
fitted and avoid the possibility of a screw or pin seizing! I would also
recommend that you dive into the Section 5 package and extract the Pt.
5-11 and 5-18 pin first. I found it much easier to fit these to the Pt.
4-16 before assembly of the latter to 4-15. If you do this now you can
ensure all alignments are correct, enabling the fitting of the 5-18 pin
much more easily. It may be necessary to ease the holes in the chassis
through which the weight shaft 4-14 slides if it is considered too tight.
Next use your finest file to smooth the surfaces of the die
blocks and expansion link inner radii. These have been manufactured using
laser cutting and the rubbing surfaces need cleaning up to reduce friction
between them. Careful fitting in this section will ensure smooth operation
of the expansion links that is essential.
Examine Section 5 drawings carefully and be sure you
understand how the valve adjustments work. Note that the dimension given
for the length of the reach rod is a nominal figure of 181.7 mm and some
small variation will result during the valve setting process. This will
occur when adjusting for the correct position of the die block in the
expansion link. Also note that though the drawing says that it is
important to make parts 4-11 and 4-16 appear in phase it is only practical
if tolerances allow. Rather, it is imperative to ensure that with the
reverser set in the mid gear position, both of the die blocks must be
exactly half way down the expansion link.
In Section 6 you aim for equal Laps 1 and 2 and separately,
S1 and S2. This is achieved by varying the length of the valve rod Pt. 5-6
by using a screwdriver in the front of the valve. To achieve this you must
have locked the threaded end of the screwed rod INSIDE the valve first
using a thread lock. When assembling initially you set the valve rod to
9.5 mm between the back of the valve and the fork end nut. You then loosen
the nut to allow the adjustments to be made. Rotating the valve with the
screwdriver in the slot in the end of the valve will lengthen the distance
set nominally at 9.5 mm. This will vary as the valve is adjusted to give
the correct Lap1=Lap2 and S1=S2. On my example Lap1=Lap2=2 mm and S1=S2=3
mm. Air testing will prove whether you have the valves correctly set.
My air test was completely successful and showed no leaks
from either the cylinder drain cocks. I always soak my pistons in steam
oil with the rings fitted prior to fitting to the cylinders. But even if
this isn’t the whole answer, after a short period of running with live
steam in the cylinders the rings ‘swell’ and no further blow-by will
There are no difficulties in Sections 8, 9 and 10 but don’t
forget to keep the nut on the lubricator pipe raised when installing the
saddle in Section 9. It is important to make sure that the oil pipe is
always sloping upward to ensure a good oil feed.
Before fitting, polish the dummy drain cock castings using
a small brass wire brush to obtain the right finish. Also, I would
recommend adding a small washer on the shaft of Pt. 9-13/14 behind the Pt.
9-15 dummy Mechanical Lubricator. This will prevent the shaft working in
and out of the bearing in what is a very delicate assembly. I hope Aster
have lots of spare Pt. 9-17 operating rods!
As an interesting aside, whilst visiting the West Somerset
Gala a few years ago I had a storming run behind 92214 from Bishop’s
Lydiard to Minehead. I went down to chat to the driver and whilst talking
I drew his attention to a badly bent operating rod [the full size Pt.
9-17]. A fitter was called and it was found to have been caused by a very
tight fit in the rod end bearing causing a partial seizure. It could have
been expensive if not fixed!
Building the boiler assembly is straightforward and the
only note I would add to Section 11 is to ensure that when you fit the
regulator you should engage the thread at the backhead end of the boiler
far enough to ensure that the restrictor Pt. 12-10 can be fitted in the
centre of the access hole in the top of the boiler. Use your new pump
handle provided in the kit to centre the upper and lower water gauge
fittings Pts. 12-2 and 12-7 before inserting the glass. Since I always
drive my engines from the left hand side where possible, I fitted my
regulator handle at the 9:00 o’clock position and not the 3 shown in the
It’s helpful to anneal the pipe 12-4 before fitting as
softening it will make bending it to the correct shape easier and avoid
The subject of boiler insulation should next be considered.
I always fully insulate my boilers and I did so again this time. Aster
don’t provide enough material to do this in the 9F kit and additional
material will have to be purchased from one of our suppliers. I make up a
paper template and use this to avoid
wasted insulation material. This can be ‘faced’ with a sheet of baking
foil for added advantage and greater efficiency. The dressing of the
boiler outer casing or cleading is fairly straightforward though care
needs to be taken to avoid damage to the beautiful paintwork. When
installing the inner boiler to the outer casing take care to ensure that
you have the front ring Pt. 14-1 properly fitted with the holes in the
right position. Check against the saddle and smoke box casing.
In Section 15 be careful to align the superheater and
blower assemblies so as to have correct alignment of the blower with the
chimney. This may need adjustment later but will be very difficult after
closure of the smokebox top half. When fitting the boiler assembly to the
chassis, be careful to align both the superheater header to the main steam
pipes and lubricator and yet making the lower attachment bolt M2.6-6
locate correctly. I recommend loosening the boiler to backhead plate bolts
to make it easier to fit the two locating M2-4 support bolts at the bottom
edge. Be quite sure that when you fit the Pt. 16-6 water connection bolt
that you have the correct one with the slotted end.
Cab assembly and fitting in Section 17 is without
difficulty but note that the dummy reach rod guide is not fitted until
Section 20 by which time you will have got used to fitting 1.2 mm screws!
Note also that the reach rod 20-2 is only just long enough to mate with
both ends and I used an epoxy glue to hold it in place.
Section 18 goes without significant problems but note that
the disc of insulation fitted to the inside of the smokebox door is 50 mm
in diameter not 60 mm. When fitting the smoke deflectors in Section 19
make sure that the upper supports Pt. 19-1/2 are the right way round. The
gap between the middle leg and the back leg is the shorter. Before bending
the copper pipes Pt 19-9 anneal them to make bending easier but remember
to polish them afterwards to remove the inevitable oxidation.
All pipes and wires should be bent to shape using the scale
templates at the back of the drawings. No annealing was found necessary
for these as they are of smaller diameter. The wonderful casting provided
to simulate the injectors and associated pipes on the right hand side
under the cab needs careful polishing with a small wire brush to reduce
the too bright finish. I use a gun blue to make the finish look more
weathered and realistic. The valve bodies should be painted satin black.
Much to my surprise the burner for the 9F has smaller
diameter tubes than I expected. I have fitted 25 strands of wick material
to each tube and they protrude from the top by 13 mm which is my own
assessment of what I think is needed. There is nearly always room for
adjustment here I find and your fuel and operating conditions may vary.
The tender is a very straightforward build and there is a
little on which to comment other than on its beautiful construction and
finish. In Section 24 don’t fit the dummy pipes to the 24-1/2 strainers
until after fitting the horn-cheeks and axleboxes as it hinders access to
the fixing bolts.
completion the next step was a run on the rolling road where it worked
perfectly straight off. There was no blow-by from the pistons or the
valves and no leakage from the drain cocks either. I ran it for 50 minutes
on one tank of meths and it consumed 2 1/2 tenders full of water. Each
time it was filled up to just under the by-pass return pipe. I thought
this a spectacular performance straight off the work bench.