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A web-site by Rob Speare


'D & S Lines.'

A Merchant Navy in B.R. Blue, built in Johannesburg, S.A.

Words by the late John Bradley.

After the completion of a Martin Evans' "Green Arrow" in September of 1999, I started the search for another project. 
I have been asked why - out of all the well-designed and detailed series in the Model Engineer - did I choose 'Ariel' by Keith Wilson ?   The only answer I can give is that, in my youth, I was inspired by the S.R. "SPAM CAN", and of all the Bulleid designs, 'Ariel' was the only designer series I could find.

All the drawings, etc, were taken from the Model Engineer publications.  Those prior to my collection were obtained from a club member, and all copied to A3 for easier reading.  I was told that I was mad to try and build it, because of all the errors in the ME articles.

All the wheels for the loco were machined from cast iron round bar, using my Maximat lathe, Emco 7 mill and dividing head.  To avoid possible "snide" remarks by club members, both sides were machined, the pony set being done first (as a practice set).

Even though I had the full design series and could have made the main frames at this stage, I decided to make components as per the articles, and therefore the motion bracket fabrications were next.  Manufacturing these items was not easy, as all dimensions had to be checked and assemblies done in several stages, taking care each time that previously silver soldered joints did not melt, and all "fall down".

It was at this time I obtained from Keith Wilson, the error list applicable to the design, and I hoped this would eliminate manufacturing scrap ! ! !     In all, fifteen errors were listed, however, there were quite a few more.  One on the "pony truck" was fortunately avoided by using 3mm plates, instead of the stated 3/32 inch; a later article rectifying it to 1/8 inch.

As mentioned previously the driving wheels were machined from solid, also the axle boxes being cut from round bronze bar.  It was fortunate that my son went to the U.K for a holiday, and he bought me back a set of horns obtained from M.J.Eng. which were machined with great care.  The main frames were laser cut from 3mm plates and care taken with hole positions, etc, as per error list.

It was found that the buffer beam gussets as drawn had to be altered, so that the buffers could be fitted.  Assembly of the frames did not cause many problems, remembering that certain holes retain brackets and horns.

An added stretcher to my design, based on the one for 'Green Arrow’s' axle pump was added to carry a similar pump, an eccentric fitted to the rear driven axle, to drive the pump, was fitted when the wheels were being assembled onto the axles.  Main springs had to be designed to suit spring steel, as the phospher bronze recommended, was only available in sheet and cost a fortune.

Next on the list, was the motion work, etc, the connecting rods, only had minor dimension errors, as did the cross heads and guide bars.  By this time, I realized that one had to read ahead before manufacturing, as what you made today may not fit tomorrow ! ! !    Now, we come to non-existent drawings of suspension links combination levers, union links, valve rods, rear valve guide and inside front valve guide.  Fortunately the articles did have a dimensioned line diagram of all the linkage, and from this I made my own drawings of the components required.

For the inside front valve guide, I used the 'Green Arrow' design.  The rear ones I based on the blind cover, as used on Martin Evan's "Jinty".

Having obtained a cost for importing cylinders casting from M.J.Eng., I took a couple of brandies and went to the drawing board.  There fabrications were drawn up to suit hollow bronze bar and plate obtained from the scrap yard.

The first of the cylinder operations was machining mating surfaces, the overall dimensions leaving enough for final finish and port ways.  Dowels were installed in the mating surfaces and flattened silver solder, with flux clamped between the two parts.  I must admit that I did not anticipate the amount of heat required to “cook” the job, even when enclosed in firebricks.

Now I had three chunks of bronze, which required bolting faces, and top plates in the case of the outside cylinders, which also formed the inlet chamber, and the smoke box saddle components for the inside cylinder.

Fixing these was somewhat easier, and the use of the large nozzle in the oxy-accetelene torch was adequate for this job, when surrounded by firebricks.  The inside cylinder steam passages were created using brass plates, and this centre cylinder was obviously the more complex.  After testing to twice working pressure and closing leaks (and there were some), the machining was completed, taking note of the errors list that suggested that overall length of outside cylinders be increased.

Construction of the Bissel truck was made easier using a programme called scale print, which allowed me to blow up magazine drawings to full size.  The drawings produced allowed me to bend metal to “jig” for want of a better word.

At the start of 2002, I made a start on the boiler, deciding to incorporate thermic siphons as per the prototype.  I was about to send drawings of the formers for laser cutting, when I was told that a certain Mr Sawyer had already made these formers for his MN, and after a phone call I had the items on loan, and commenced “battering” copper.  The combustion chamber was constructed first, it being fitted with blind bushes for rod stays.  The reason for crown rod stays was that boiler codes were being discussed, nationally, and the Australian code appeared to be getting the most attention.  It decreed 'no girder stays', better safe than scrap ! ! !

Pressure testing a combustion chamber is never easy I was told, and mine was no different.  The tubes were made over long and soft soldered plugs installed.  A brass plate was made to the size of the firebox throat, and soft soldered in place, making sure that the solder did not encroach on areas to be silver soldered in the future.

We now have a partly built chassis and a boiler without any fittings, etc. these not being described in the "words and music".  The smoke box, apart from being large, was not that difficult, the door casting being obtained from M.J. Eng.  General fittings manufactured were as per designed, with exception for the turret supply pipe, which I could not bend to suit the required radius.  In the end I made a banjo connection.  As per the now famous correction list, the regulator body was pruned to get into the "holes" and with it's operating rod, was juggled into the boiler.  One comment worth making is that I believe the rod does not have adequate gland support surface to compensate for the straight-line pulling effect, as the gland requires regular packing adjustment.

Pressure supplied from the test hand pump was via a tube end plug, tapped to take a M.E. fitting, and when the test pressure was applied it did not leak.   Success !

The thermic syphons were pressure tested before assembling into the firebox, and rod stay holes drilled into the boiler shell to match the bushes in the firebox crown.  In retrospect, this boiler must have the strongest crown of any, as the siphons are a stay of their own.  The boiler passed it's Club test in September 2002, though not without having had to close small leaks.  In my case, it always seems that you repair one leak and another one appears, and always at the top end of the firebox.

Construction of the grate, and in particular the ash pan, required considerable thought to get it to fit between the frames.  When the completed boiler assembly was tried in the frames and the loco put onto the track, it was found that the ash pan doors would not drop open enough, due to them holding on the rail.  This problem was overcome by replacing the hinged doors with one long removable sliding door, located closed with a through pin.  At this time it was also noted that should the grate have to be removed, the complete boiler assembly and smoke box would have to be lifted.  Whilst the boiler assembly was out of the frames the cloathing (please note the correct terminology) was made up, locating the hand rail stanchion supports as per drawing.

After the cylinder supply pipes and super heater had been completed (and tested) it was decided to see if the wheels would go round.  As the cab reverser was not made, the weigh bar was operated via the lifting screw and nut.  The supply from the compressor was fitted with an inline lubricator and the air supply opened.
It ran ! ! !

The reverser as designed required the making of the crown wheel and worm, I dodged this operation by using gears from some printer units, the tooth width being similar to a metric screw pitch.

This loco being fitted with calliper brakes required twice the amount of components as normal and was a tedious task.  The pins holding the bits together were too small for a millimetre diameter split pin, so I made my own from paper staples.

The last major component was the cab, a former made from timber assisted bending the metal.  For ease of driving the top section was made more removable.

The manufacture of running boards and smoke deflectors was straightforward compared to other work.

The lubricator as proposed was rejected, as I considered the drive rod too long (and also it meant stripping out the front end to fit it).  In it's place two standards units were mounted on the running boards, each feeding a common manifold, supplying via check valves, the three cylinders.  For inside motion lubrication, pipes from the mock sand box inlet were used.

Tender frames were laser cut, the DXF file being made by my son, who is very proficient with CAD, horns were fabricated and axle boxes cut from solid bronze bars.  Two components that were not clear from the drawings are the drawbar and safety links.

Whilst on holiday I visited the Bluebell Railway and took photos of methods of fixing, and dimensions of the links and the draw bar.  It is worth a mention at this time that my loco and tender remain coupled up, as to disconnect all the pipes and links for a meeting is an hour's work on its own.

The tender wheels were machined as previously, however I only did one side with holes as no one would see or feel underneath.  Manufacture of the tender brake gear was as tedious as the loco, and as no return springs were shown on the drawings for the vacuum cylinder, I did not fit any.  The latter is to my regret, as when the ejector (which works) is used, the cylinder friction holds the brakes on and have to be released using the hand brake screw.

The tank was constructed from brass plate, 6mm angle and square bar, the jointing surface were coated with epoxy resin and fixed with counter sink brass set screws.  So that the cab controls could be reached, the bunker and cab sections of the tender were made removable, with detachable handles for the injector valves mounted under the tender footplate.

For the lighting power supply, I made the vacuum receiver tank into battery holders to take 3 x R14pp, 1,5v batteries, which powered, via a circuit board, 12 LEDs; painting of the loco was done by brush, having had no great success in the past with spraying.  The colour blue was decreed by the directors of the "line" saying one green loco in the shed was adequate, and the M.N. would be in B.R. express class 8P blue.

The first steam trail for the completed loco was in August 2004, which showed up numerous problems, namely, tender to the loco height did not match, springs loading, blast pipe and exhaust nozzle size, also injectors and axle pump supply.  Rectification of these problems took time and in particular, the blast pipe and trials with various size nozzles.

In conclusion, the building and subsequently running trials was a project that exacted all mechanical disciplines; I now have a good looking and powerful loco that like all, must be run regularly, otherwise “rot” sets in.


**  Editor's Note:  The 'Merchant Navy' name was never a prototype; John told me it comprises the initials of his daughter and daughter-in-law's christian names, with 'Lines' being his late wife's maiden name.

In 2011 John completed an amazing model of the Gresley 4-6-4 'Hush Hush'; a complex project complete with the correct yarrow type copper boiler in 5" gauge; there is a photo of John with his new loco in the Gallery.

It is with sadness, that John passed away on the 31st October 2011, after a short illness.  Moving to S.A. in the mining industry, John later became a leading character at his local club, the Rand SME near Johannesburg.

John made regular trips back to the U.K. and enjoyed visiting many model engineering tracks and a had a fondness for 'Tornado', visiting it several times during construction; in 2011 he visited IMLEC held at Bromsgrove, one of 9 Bulleid builders attending. 
We have lost a tenacious researcher, a very talented engineer, and a man who cared deeply about his family.