The Story

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!

 

Gas Firing

 

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 to appear.

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 band drive.

 

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

Shielding

 

This beast still used the "rat-dropping" burner, which needs shielding from draughts. These Meccano flame shields will make up the firebox.

Metal-bashing

 

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.

More metal-bashing

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.

A Cab

 

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.

Detail

 

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

Painting

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.

Adjustments

And here it is with a smaller flywheel, curiously from a Regner Konrad (thanks to Rob Bennett).

There’s also a new gas tank, a second from Cheddar Models

Conclusion

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 stud.

 

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 horror.

 

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 radius curves!

 

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 the tank.

 

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.

Five Videos of the Thing in Action

The Thing au naturel 1              The Thing au naturel 2

Video 1          Video 2        Video 3

WARNING - these videos are BIG (2 Mbytes each)