This is the story of my first attempt at building (or bodging together) a steam locomotive.
The Coffee-Pot had shown me the advantages of geared locos, and I'd successfully
modified it, even making my own coupling rods. I felt it was time to go one step
further. Not having the machinery or skills to make my own boilers and cylinders,
I decided to buy those in and start from there. eBay had a rather nice stationary
engine from Wilesco for just sixty quid, there was already a stack of Meccano and
a selection of wheel sets in my workroom, so I was ready to start.
Many people have helped with this project, too many to name individually. However,
first and foremost, thanks go to Liz for buying me a Meccano set for Christmas and
being patient for over a year while I got around to using it.
The Power Unit
The Wilesco D14 stationary engine (with double-acting single cylinder and slip eccentric
valve gear, for the techies)
I bought the beast and before ripping it apart, I ran it a few times on the "rat-dropping"
fuel tablets, and was well pleased with its performance. It disassembled quite easily,
with a minimum of BFI (Brute Force and Ignorance), leaving the boiler and cylinder
as a single unit.
Now the real work began!
The next step was a crucial one - the fitting of a butane gas tank and burner, supplied
for a very reasonable price by a fellow member of the 16mmNGM discussion group.
The gas tank is connected to the burner by braided silicone tubing and held on by
cable ties. This seems to have worked well. Note that the wheels were now connected
by a Meccano sprocket and chain drive - this feature remains in the final version.
Also the frames have been shortened and the skeleton of a footplate was beginning
The Test Bed
Just for once, I'd prepared myself before spending money on the materials. I set
about building a test bed for a geared chassis, using Meccano components, including
a very rapid electric motor. This was fitted with belt drives and a plastic gear
train, to produce a beast that ran at a sensible speed. For a narrow gauge line I
believe that’s about 10-15 MPH. Some would disagree, and seem to have Mallard's record
in their sights.
Many of the features of the finished beast were already there - the Meccano frames,
the mixture of belt (later, chain) and geared drive and the use of Bachmann metal
wagon wheels. It ran sedately and powerfully enough to convince me that the project
was at least possible.
The Pigsty Hill Light Railway - a Very Small Garden Railway
The Thing or ‘HEDGEHOG’ - A Bodgeller’s Steam Locomotive
The Prototype Running Gear
The next step was to mount the steam power unit on the test bed and link it up with
Very crude, and the boiler was much too high but, nonetheless, it worked!
The Beast Evolves
Now to build a made-to-measure frame and add the power unit - note that all the
drive is now by bands - gears will re-appear much later on.
The Final Product (1)
Finally the Meccano sprockets, chains and gears, ordered from John Thorpe Meccano,
arrived. The front end was completely rebuilt, and the sharp-eyed will notice that
the steam exhaust has even been moved forward half an inch.
The right-hand side - all sprockets and chains
This beast still used the "rat-dropping" burner, which needs shielding from draughts.
These Meccano flame shields will make up the firebox.
Now to start making the beast look like a real locomotive:
The smokebox is made of thin brass sheet wrapped round the boiler and bolted to the
footplate, and the side tanks are made of thicker brass bent and soldered into shape.
Note the smokebox door - not the future name of the loco as some have suggested,
but the only thing I had that fitted.
I searched for the right shape and, in a hardware shop, I found a rose for a doorknob
and decided that would do.
The small (10BA) bolts in the smokebox, with the nuts outside and the shafts cut
flush with a slitting disc, hold two thin brass strips bent into circles. These form
a seat for the door, which is sealed with silicone adhesive. The whole is finished
off with the badge of the 16mm Modellers Association. Steam from the boiler (the
bent stainless steel pipe on the left) is diverted by silicone tubing and a brass
tube up into the smokebox and thence out of the chimney (brass tube which was in
my bits box). The thin steel strip Meccano strip above the side tank was a failed
attempt to stop the power unit being pulled over to the right. A much more elegant
solution was found later.
Here we see the wrap-over cab, inspired by Manning Wardle locos. It is attached to
the tanks using silicone adhesive. The large blue pulley improved performance by
increasing the drive reduction, but proved to be an encumbrance in actual use.
You'll notice that the power unit no longer leans to the right - this is because
I replaced one of the bolts holding it together with a longer bolt that rests on
the boiler and keeps it in place - simple or what?
The Final Product (2)
The Left-hand side - with gears, sprockets and chains
Standard ‘glamour’ shot
After much soul-searching, I decided to paint the Thing (black, of course).
The boiler and chimney are heat-resistant black over non-ferrous primer, the rest
standard car paints.
And here it is with a smaller flywheel, curiously from a Regner Konrad (thanks to
There’s also a new gas tank, a second from Cheddar Models
This will probably be the final configuration - now it's well run-in, it performs
very well at a reasonable speed. It takes about three minutes to do a complete circuit
of my line, which is just right for sipping a cold, or indeed warm, drink. The flywheel
and slip-eccentric valve gear make shunting a doddle (except that you have to remember
that the flywheel moves in the opposite direction to the loco).
The beast is now named "Hedgehog" and is a valuable part of the PHLR's motive power
What I Learnt from Building the Thing
1. The Yahoo! 16mmNGM e-group is a wonderful resource for advice and practical help.
Thanks to all who offered either and to all who commented, either in delight or in
2. Don't be satisfied with the first design. Try moving things around, both on the
loco and in your head. Meccano makes this a whole lot easier but, by its modular
nature, limits your design options. This may, or may not, be a good thing.
3. When you think you've got a good design, don't judge it on its first run.
a) Run it in well, keeping it lubricated. This applies just as much to bought-in
locos, as some on the e-group have found - not every manufacturer runs its locos
in like Roundhouse.
b) It helps to have a tight, sloping indoor track - you can't simulate the icy blast
and bitter cold of an English spring, but you can make it more difficult than its
eventual habitat. A circle of Mamod or Large Gurt Big on the kitchen/garage/futility
room floor is not to be sneezed at. It'll rejoice when it's let out on four-foot
4. Lubrication is vital - repeated to emphasise my point. Thin for bearings and linkages,
thick for cylinders and gears.
5. Just about any steam engine will provide enough power to drive a useful loco -
it's just a question of how far down you're prepared to gear it.
a) Five (scale) miles and hour is a perfectly reasonable speed for an industrial
loco, and ten for mixed traffic, on the kind of lines most of us model. Of course,
it's different if you're modelling a Festorail IC 125, but how many of us do that?
For that matter, would you rather have a sip of your nice cold (or hot) drink and
wait a couple of minutes for the next train to come by, or watch it whiz round like
a demented hamster.
b) Bear in mind that the effects of friction are worst at the high-speed low-torque
end. This is not the place to put the gearing, but a chain drive will work very nicely
- the gearing can sit further down the power train.
c) The Wilesco single-cylinder double-action engines are a snip at sixty squid and
have gurt great boilers that'll give a good long run.
6. Getting a burner right is a black art, whether gas or meths (alcohol in the USA),
just as it is with a real coal-burner. With gas, I've learnt to be sure that:
a) The thread of the jet is sealed. I've used silicone adhesive, which seems to do
the business. DON'T GET IT IN THE JET! If the jet gets blocked, blow out the gunge
with a blast of butane from the can.
b) Sufficient air is dragged into the burner - it helps to have the gas jet just
showing in the air intake. You can tell this isn't happening by yellowness in the
flame, soot everywhere, and ringing carbon monoxide headaches.
c) The burner is level - otherwise all the combustion takes place at the top end.
d) The flame is even - a copper mesh over the burner may help here.
e) The burner is the right distance below the boiler. "What's that?", I hear you
ask; consult the authoritative volume "Trial and Error", by A. Bodgeller.
f) The gas tank doesn't get too cold so it won't supply enough gas - I've built a
heat conductor from Meccano so a little (NB, a little) of the burner's heat warms
g) The burner's heat is confined around the boiler. Side tanks help here, and the
Mamod is well nigh perfect in this respect.
h) Yes, it IS complicated - how long do you think it takes to become a trained fireman?
7. Reinforced silicone tubing is excellent stuff for connecting gas tank to burner
(fix it firmly with cable ties) and leading exhaust steam up the chimbley. PPS Steam
Models do the stuff at a very reasonable price.
8. Look for bits and pieces that will fit your needs:
a) The smokebox door is the rose from a doorknob fitted with a 16mm Association badge.
It's sealed with silicone adhesive, a very useful material that I've also used to
fix the cab to the side tanks.
b) The wheels are Bachmann large wagon wheels forced off the original axles and on
to 1/8" steel rod. These are brought up to Meccano's 5/32" by slipping brass tube
of that diameter over the outer end of the axles and superglueing it on. A separate
set of 32mm axles has been made from Meccano rod.
Nothing exceeds the pleasure of watching a loco you built and designed yourself trundling
along your railway. Even the multi-thumbed with no lathe and no engineering training
can do what I've done. Whether they'd want to is, of course, a very different question.