Conway Castle. (A Tram-Drivers Hobby)

John B Harrison.

Originally published in 'Garden Rail'.

Update: A new clutch

A First Attempt At 7¼" Gauge.

For years I have watched and envied people who have owned and driven their own locomotives, but have never had the time, money, or inclination to build one of my own; or so I thought.

I have modelled in various scales over the years i.e. 2mm, 4mm, 7mm, 7mm narrow gauge, 8mm narrow gauge, 10mm, and 16mm narrow gauge (SM32).

The latter introduced me to `heavier` scratch building; everything but the motors and gears were hand fashioned.

After a visit to `Halton Miniature Railway (a mile long 7¼" gauge track in Runcorn, Merseyside) and seeing their petrol driven loco`s, I realized that a loco could be built with reasonable ease and quite cheaply; especially as I am adept in the art of scrounging!!!

spacer a1

Conway Castle.

Most of my 16mm scale models are of `Ffestiniog and Welsh Higland Railway` prototypes, being an ardent fan of the railways, so I didn't have far to look for a large bodied Diesel prototype to base my model on.

At the time, `CONWAY CASTLE` was the FR’s largest Diesel (now dwarfed by their new Funkie bogie Diesels) so I decided to build a 1/3rd scale model of this. The reason I wanted a `large` prototype, was so that the model would be big enough for me to sit in.

4" to the foot works out at 8" gauge so it would not look too far out and would make scaling up of the drawing a lot easier.

The `Ffestiniog Railway` drawing of `CONWAY CASTLE` is in 7mm scale, so a larger working drawing had to be made with all the basic sizes on it, this was done with the aid of a magnifying glass, steel rule and a calculator (basic model-making equipment!)

1 Author, Town Park, Halton, Runcorn



This had to be strong enough to hold the engine, gearbox and a driver three times too big. The idea was to manage without a driving truck for which another four wheels would have to be made (or scrounged). As it turned out, after about six years, the driver put on weight and could not fit in the loco anymore so the wheels had to be scrounged anyway!

I think I went over the top strength-wise and bought some 3" x 1½" Mild Steel Channel. A friend of mine turned the wheels and I turned and ground the axles (these were made longer than required, in case I ever needed to run it on 10¼" gauge track; `CONWAY CASTLE` was originally 2'6" Gauge, so in 1/3rd scale, mine could be too.

Some other friends made the gears for me and I bored out the gearbox and axle-boxes to suit the bearings. With all the `friends` that have helped so far, it is definitely workshop friendly, or actually more like a co-operative!

Bearings (both roller and needle) were picked up from scrap-yards or scrounged from different places, so only one or two had to be bought.

Axle boxes.

These are not made as prototype, but are, for ease of construction, split blocks bored out to suit axle roller bearings and once split, bolted together to tighten onto and hold the bearings in place. These in turn are secured to the sole bars. One set were welded directly to the sole bars, the other set, milled slightly smaller than the first, on the top edge, and fitted with car engine valve springs. The latter are slipped over pieces of Stud Iron screwed into the tops of the axle boxes, and fitted through clearance holes in the sole bars. Nuts are then welded in place on to the top of the stud iron to hold the axle box in position; enough clearance was left to allow vertical movement.

The sprung axle is driven by segmented rubber belting and pulleys from the fixed axle. This type of belting allows the correct tension to be maintained; unfortunately, I couldn’t scrounge this!


The engine for the job soon sprung to mind. A few years ago, my father had decided that “ A `OVVER was less BOVVER” and bought a `Flymo`. He duly donated the engine complete with the mower it was attached to; a 1965 14” `Suffolk Colt`(Cast Iron Block version).


The drive utilizes most of the sprockets and chains from the `Suffolk Colt`, also the clutch, which is the centrifugal `automatic` type. The clutch is fitted to the engine as it was on the mower, with the addition of a pulley for a possible future alternator /dynamo drive.

A sprocket on the end of the clutch drives a large sprocket (which is now reduced to approx’ 3 : 1 ratio) supported further forward on the chassis, above the driving axle. This larger sprocket is on the end of a shaft which is supported at each end from above, with roller bearings in housings. Also on this shaft, between the bearings is a rocking gearbox for reversing. The Drive for this is by means of another 3:1 (approx) ratio sprocket/chain arrangement (on the other end of the shaft). This drives two meshed gears, which when the whole assembly is rocked one way or the other, drives another similar sized gear, on the fixed axle, forward or reverse. The loco is held in gear by a 3-position lever in the driving cab. The above is a lot more difficult to explain than it was to build!

Supports for all the shafts, etc., look a little hap-hazard, in fact rather like one of the late Arthur Dooleys` sculptures, but my excuse is that this was my first project in Arc-Welding too! Although most of my early welding looks like something Pigeons eject from their rear ends, there was plenty of it, so everything `sticks` together quite nicely………. AND IT WORKS!

The throttle cable from the mower was also utilized and later bolted in the cab, below the rear cab windows.


←Essential if somewhat undignified entry


          Sons, Sean & Derek 1991 ↑


The existing silencer/exhaust, was removed (as it would have been very unhealthy for the driver; gradually filling the loco up with fumes) and replaced with a straight through pipe. Later, this was removed as I was running out of ear plugs! Besides the noise, with no back pressure, it was ripping the insides out of the engine!

A new silencer was fabricated using a piece of 4” x 1½”rectangular steel box-section about 5” long. The ends of this were blocked off by welding on pieces of steel plate. These had been drilled, at opposite ends, to accept steel conduit piping. A piece of second-hand conduit had its threaded end cut off, about 7” long, and about 2” from the cut end, a ⅜” hole was drilled right through. This pipe was pushed right through one of the drilled holes in the new silencer casing, until it pressed up against the other end cap. A second piece of conduit (again threaded one end only) was cut to suit the distance from the inside of the silencer end plate nearest the engine, to about one and a half inches from the cab front. This, from the cut end, had several slots `hacksawn` into it (about an inch apart) alternately, each side. This was then pushed into the other drilled hole in the silencer casing and welded up. The above would cause back pressure and quieten the exhaust quite considerably.

Once welded up, the silencer was screwed into the exhaust port of the engine and a 90 degree elbow fitting screwed onto the other end. Into this, another length of conduit was screwed vertically, and fastened onto the cab front with suitable conduit fittings.

The loco looks very realistic when idling, waiting for the next turn of duty, with the exhaust smoke coming out of the right place!

Chassis Trials.

The first run of `Conway Castle` was……… how can I put it………SLOW!

Mowers only do about 2 or 3 MPH and on its first run, so did `Conway Castle`.

After removing the governor, there was a slight improvement, but I still had two kids jogging on the spot at Halton uttering the words ……”It don’t go very fast, do it mister?”

The gear ratio was altered as mentioned earlier, and on the second trial, it managed about 10 MPH approx (no speedo as yet) and gave the afore mentioned kids a good run for their money!

After the first test run, I made some coupling bars out of 1” box section; one end has a copy of the Ffestiniog `Buffer Coupling` welded onto the box section the other is just box section drilled so that a long 10mm coach bolt can be dropped in to couple up the wagons, etc. On the second run, an 8 seater coach/wagon was loaned to me by some members of Halton Miniature Railway society and the loco duly earned its keep; although, some `muck` in the carburetor brought things to a standstill after about the fifth mile run and the humiliation of being towed in by a steam locomotive put an end to the days’ proceedings. One member spouted up “It’s very authentic; just like the real `CONK-OUT` CASTLE!”

The Ffestiniog used to have trouble keeping their Conway Castle running too! £1.50p for a petrol filter seemed to sort this problem out.

1 Sean at Greenleys School Fair, Wallasey, June 1997 ↑ 1 Modellers Weekend, Bala Lake Railway 1992


Once the drive was sorted out, thoughts turned to the body. Most of this has been built from odd pieces of plywood, chipboard and scrap aluminium sheet (mainly damaged panels from old buses; courtesy of another friend!); we also must not forget loads of pop rivets and self-tapping screws.

A radiator grill was fashioned out of the wire lid from our old hamster cage; I must add that our `old hamster’ had already vacated the premises several years before!

Before the upper part of the body could be completed, the driving position had to be planned. I worked out that if my feet could fit between the buffer beam and the rear axle (feet either side of the reversing lever) then they would be hidden by the dummy sand boxes on either side and give extra height to the driving position. This allowed me to sit on a platform under which a 12 volt car battery could be housed for powering lights, air horns, etc.

Sitting in a more vertical position meant that my head and shoulders would stick out of the cab roof; this I had to live with, as I am squeamish and did not fancy the surgery involved to make me fit the cab!!!

The problem next was the entry and exit from the cab. The roof as such, had to be a token roof and was arranged so that one set of side windows and gutters, hinged down from the body waistline. When closed, it could be secured with two small door bolts.

Just recently I have altered this set-up, having passed the age `when life begins` and acquiring a new Michelin spare tyre or two, it has become a bit of a squeeze fitting in the cab, so a full roof has been fitted and the controls moved to the outside rear of the loco. I now drive it from a match truck (a copy of Ffestiniog ex RAF open wagon No. 87).

Buffer beams were cut out of plywood, slid over the buffer couplings and bolted onto the front of the sole bars.

The bonnet over the engine compartment is about 1.5” wider than scale to fit the engine gearbox arrangement without too much hassle. Also, the real Conway Castle has side access doors. This would have hampered engine starting and maintenance, so the whole bonnet, sides and exhaust cowl were made as one piece and made to hinge forward. Door panels were represented after painting, by ⅛”self-adhesive lining tape. (I think supplied by Tenmille Co. for model planes).


These were made as simple as possible and nothing like the real loco`s brakes.

A frame was welded up from angle-iron, the same overall width as the wheel-sets. Across the top was welded a ½” diameter bar (again from the `Suffolk Colt`) which was cut off to fit between the frames. In the sole-bars, two ⅜” holes were drilled and after fitting 2 mahogany brake-blocks to the frame (cut out to suit the wheel Diameters), the assembly was bolted between the frames and allowed to swing back and forth.

A long piece of Stud Iron was cut to length and bolted loosely into a ½” hole drilled in the centre of the assembly cross-bar.

A hand-wheel I had, off a small scrap lathe, made a brake handle. This was originally inside the loco`, but now protrudes out of the rear end. To this, is yet another piece of Stud-Iron, connected to a pivoting nut on a pivoting arm, made from 1” angle-iron. At the other end of the arm is a hole through which the other piece of Stud-Iron is fitted.

When the hand-wheel is rotated, it pushes the pivoting arm which, in turn, pulls the brakes onto the fixed set of driving wheels and stops the loco extremely well; sixpences spring to mind!


Headlights were a problem for a while, there are four of them and they had to have reflectors and chrome trims!

A chance visit to a local discount store soon found a solution; chrome plated Chinese torches, 50p each. Four were quickly snapped up and once home, were be-headed at the top of the battery holding shank. The heads were pushed into holes cut into each end of the loco and glued in with Araldite. The backs of these screwed off for wiring and bulb changing. From Maplin Electronics, half a dozen six volt pea bulbs were ordered and once wired in series, connected to a single pole, double throw, centre off switch (what a gob full). They were then wired to the battery and worked! A double beam shone about 15 feet in front of the loco, and when the switch was flicked over, the same behind!


The prototype has a large brass horn fixed between the rear cab windows; another problem! If I leave it a while and do something else on the loco, it might sort out later, I thought. This time it worked.

A friend of mine bought some new twin air horns for his car, fitted them and then; his wife didn’t like them! “Would you like to buy a pair of `once used` air horns for a fiver?” I nearly pulled his arm out of its socket!

The smaller of the two was chosen looking about the right size, and the horn part cut off. The resonator was pushed through the hole I had drilled in the required place and bolted to the body from behind. The horn was then primed and sprayed in gold car enamel and when dry, fixed back onto the resonator using a piece of plastic hose, also suitably gold plated.

The compressor was then bolted to the sole-bar, on one side, and wired to a push switch, a small car battery and a 10 amp fuse. The horn was piped up in nylon pipe and push in connectors bought from a pneumatic supplier, and when tried, it sounded a little tinny. To rectify this, I bought a few more fittings and piped up the larger horn under the long bonnet and out through the `hamster grille` front end and now…………….NOBODY WALKS ACROSS THE TRACK IN FRONT OF THIS LOCO!!!


All of the chassis was painted in `Smoothrite` paint which should slow down the rusting process a bit.

For the rest of the loco an all-over coat of Grey Primer was given and a visit to Boston Lodge, Porthmadog arranged.

On arrival at Boston Lodge I found `Conway Castle` ticking over in the yard and a group of electricians working on the push-pull control gear.

A driver was waiting to try it out, so I asked him if he knew what colour `Conway Castle` was, the answer………….……..BLOODY `ORRIBLE!

He did relent and found out for me that it was Austin/Rover Vermillion and light Grey; although he didn`t know the name of the Grey colour.

I went home, and the next day I bought several cans of Vermillion (much to the delight of the assistant who said it was old stock and nobody bought that colour) and a few cans of Ford Polar Grey, a colour that matched the photo’s I had taken.

Over the next few weeks, I duly painted my `Conway Castle` Austin/Rover Vermillion.

Also over the next few months, the Ffestiniog Railway (scourge of the modelling world) also painted their ‘Conway Castle’………… A DIFFERENT COLOUR!!!…………..Such is life!

Once the main colours were dry, the Black waistband was painted on in `Smoothrite` (as I had it in stock). Dummy door panels were marked on using the lining tape mentioned earlier.


This was made from double glazing type Perspex sheet, as bought from B&Q and other DIY stores.


In 1999 I decided to modify my ‘Conway Castle to look more like the Ffestiniog Railway ‘Conway Castle’ in its new Green & Cream livery. I also decided to put a roof on it and did the conversion to ‘rear of loco’ driving position.

The doors in the old version were only half doors on my loco, to allow me more room to stretch my elbows while using the reversing lever inside the loco. Although no doors are fitted yet, frames were put in, to allow full height doors to be fitted later.

A door was cut in the rear of the loco, which hinges in to allow the driver to reach the reversing lever inside.

This is much more comfortable for the driver, as before the conversion, the lever was between the drivers legs, leaving the driver in a very vunerable position if he wasn’t careful!

15 Year Gap.

A lot happened in 1999. Firstly, in February, my dad died.

July I was made redundant, and while I was looking for work I finished off a video my dad had started about the Birkenhead Tramway. Some shots were missing, so I went down, filled in the gaps, and finished the video.

September, I received a phone call…..”I believe you drive steam trains?” said a broad Lancashire voice on the other end. Next question…..”Have you ever driven a tram?” “No” I replied. “Would you like to drive a tram? If you like, come and have a chat about it.”

The caller was Noel Marsden, who was the superviser of the Birkenhead Tramway at the time. I had put my CV into Wirral Museums, looking for a change of career, and it had been passed on to Noel. I took the video camera with me to my interview and, after seeing himself on the tape, Noel put my name forward and in October 1999 I got the job as Tram Driver/Museum Technician; ending up as senior Tram-Driver/Technician.

spacer 4a

What has this got to do with Conway Castle I hear you say? Well the annual ‘Bus & Tram Show’ in 2000, run by volunteers at the Wirral Transport Museum, had my model displayed at the show. It seemed a popular display, so there it stayed; for about 14 years!!! The museum was open the same days as Royden Park running days, where I had joined the model engineering society, so I wasn’t able to get down there to run it.

In October 2013, I was made redundant by the council, who owned Wirral Transport Museum, and so Conway Castle came home again. (The museum is still open, but now run entirely by volunteers).

Conway Castle with Hong Kong tram No.69 and Lisbon tram 730 in Wirral Transport Museum, Birkenhead.

Re-Build. Continued.

By 2014 and I no longer had a trailer, but aquired an old Vauxhall Zafira….Great I thought, it should go in the back……….NOT!

The loco was 1½” too high!

Never daunted, I decided to make the roof removable…..The loco, not the car!

You could say, a ‘Conway Castle Cabriolet!!!’

5 Engine, Clutch, Gearbox, Tank, Silencer

6 Clutch and gearbox assemblies

1 Rear of Conway Castle showing reversing lever inside, with hand brake and Throttle outside

8 Conway Castle Cabriolet July 2014

I had to make the small bonnet roof, the main roof and window section, and the exhaust cowl part of the upper structure. The latter had been part of the long bonnet. There are also several new angle iron cross braces for support. I haven’t finished yet (as ever) but eventually, the roof will clip on when running; at present, it just sits in place.

I re-joined the Wirral Model Engineering Society at Royden Park, Frankby, Wirral, and so far there have been 3 test runs of loco and two wagons; FR No. 87 Ex RAF Hudson 4- Wheel wagon, and Hudson Bogie wagon FR No.63. These have also been overhauled, and the test runs were all successful.



There are still quite a few additions to make, the rest of the handrails, vents, plates, doors, etc. but these will be finished in time. I am also fitting air brakes (most of the bits acquired!!!) and an alternator for horn and lights. I have just fitted a larger clutch off a Suffolk 24” mower. This is about 1” bigger in diameter, so should give the loco better pulling power! I also have in stock numerous spray paint tins for a touch up of the paintwork!

Although everything on the loco is not brilliantly designed or executed, she does look like its big sister down in Porthmadog, and it works a treat! (one day they might meet ???)

For a first attempt in this scale, built from scratch, and initially for under a hundred pounds, I think I have achieved what I set out to do; to build my own locomotive to drive!

If anybody wants to see the locomotive, it will hopefully be a regular visitor to Royden Park, Frankby, Wirral, in the future.

To finish, I would like to thank Halton Miniature Railway, Runcorn, Cheshire, and Wirral Model Engineers, Royden Park, Frankby, for their help and running rights, also to the Bala Lake Railway for the good times had running on their track at Llanuwchllyn, and to everybody who helped in donations (?), time, experience, etc.

I would also like to thank my late father for his lawnmower’ donation’ and several loans of his trailer for trips to Runcorn and Bala.

Finally, I would like to thank my wife (who hates the thing; but still puts up with me!). This project would not have been possible if not for her endurance of my long standing affliction……………..Railways as a hobby!

I hope that article inspires other lawnmower (or Generator, Motor-bike engine) owners to do a re-build and enjoy the thrill of DRIVING ‘THEIR OWN ‘LOCOMOTIVE!

John B Harrison. (Precision Engineer)

First Written July 1997.

Updated April 2011 & 2014, and Feb 2015.



A Bigger ‘Bite’ For Conway Castle

‘Conway Castle’ was originally built in 1989/90 and was based around my dad’s old 1965 Suffolk Colt, 14” cut, Motor Mower. The loco has been great for short trains, with only a few passengers, but has often struggled a bit with heavier trains.

The loco spent a long time on display at Wirral Transport Museum (where I worked at the time) so after a 14 year break from running, in 2014 a refurbishment started. Several jobs for improving the loco were planned, but the most urgent was the clutch.

The engine, clutch and certain chains and sprockets were used from the 1965 Suffolk Colt mower; even the petrol tank and throttle cable were duly fitted! The engine is around 95cc and 4 Horse Power, but the centrifugal clutch was quite small being designed only to pull a 12” blade mower and a box of grass! After a change of sprockets it now travels at about 10-12 miles per hour, but this has reduced the pulling power.

A scan round on eBay, and another clutch was found. This was about 1” larger than the original, and seemed to fit with the existing shaft components. Before I fitted it, I had it checked out by a lawn mower specialist and found that it was off a larger, 24” wide cylinder, Suffolk mower, and did indeed match up to the engine I was using. The friction pads were also in good condition and, in his words, ”Would last for ages!”

There was one thing that was different though. Besides the larger diameter, the boss on the back of the friction drum was too deep, and put the chain out of line with the gearbox drive sprocket. The other reason for this was that I had fitted a pulley wheel onto the engine crankshaft; between the clutch and the engine. This is to drive an alternator to charge a battery to supply power for lights, horn and compressor for air brakes (Well into the future!!!). I thinned the pulley down as much as I could, on a lathe at work, and faced off about 10mm from the clutch boss length.

I removed the old clutch and stripped out the spindle that contained the dog clutch; which I was going to re-use. This only required the removal of one circlip and a gentle tap with a small persuader (Hammer!). I then took off the bearing support bracket off the end bearing. To my disappointment, the outer shell of the roller bearing was split in two halves! Onto the interweb again, with the bearing sizes, and a brand new bearing appeared the next day; wonderful service!!!

The bearing replaced, and clutch assembled, it was time to offer the new clutch assembly up into position. Despair! The gearbox support was fouling, stopping the outer drum of the assembly from sliding home onto the crankshaft! Never downhearted, out came my trusty ANGLE GRINDER!!! This quickly ‘sparked through the offending support, which had been built to my usual standard of over engineered butchery (If it works, its right!), and home the clutch assembly went; pulley and all!

The clutch assembly now fit in the right position, and the chains and sprockets all lined up. The support has not been tidied up yet, but the clutch has been tested on the track at Royden Park Frankby. Towards the end of the test, there was a marked difference in the pulling power, as the friction pads bedded in to their new position.


There are still a lot of small jobs to do on the loco, but they will get done (in between other projects, that is) EVENTUALLY!!!

John Harrison. September 2015

at Bala
Conway Castle at Bala

© Wirral Model Engineering Society 2017