NB: MY PC IS COLLAPSING AROUND ME..

So I may vanish like the Cheshire Cat, unexpectedly. Which might relieve the “mouse”…)

It will need professional attention. It had blocked access to one of my most important spreadsheets (before I could back up its latest edition), and now to ‘Word’ and Excel’ generally.  It also freezes for the Hell of it.

To business.

As far as we can determine from its documents, my Steam Accumulation Tests on this boiler were the first.

There is NO mention of them on any of its previous, SFMES, certificates. The boiler was made non-commercially in 2000, by a retired commercial builder of miniature boilers, to replace the original steel one that had expired. He was a Society member so built it as a favour to the Society. So we don’t have any manufacturer’s certificates either: it was tested as being “home-made” by a member, though I am sure he would have carefully tested it to at least the standards of the time before it was installed.

So it is possible the boiler testers were more concerned with the ability of the safety-valves to lift at the right pressure, than with maintaining it as the SAT investigates.

The initial suggestions to countersink the inlet ends of the passages, and add more holes to the cap nuts, would be first to try as they do not affect the mechanical behaviour. They simply give a freer flow to the steam.

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I have not made any engineering changes that could affect the boiler’s steaming rate – but washing the boiler out and using a particularly good coal might have some bearing on the subject.

The grate and ashpan (which never had a damper) are as fitted in that rebuild; so in theory nothing has changed since the locomotive was last used some eight or ten years ago. Though idle it has spent at least some of those years indoors, snuggled up to a radiator in Winter. (Lucky thing – comfier than its owner…)

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Another approach to the blower problem is to limit the control valve opening, e.g. by a spacer on the spindle (if the design allows) or an external stop that acts against the handle. This one has a lever-type handle, not a hand-wheel. These modifications would be simple to make and to change.

As far as I know the two manifold valves do not have captive spindles. (I’ve not tried unscrewing them!)  I don’t think retrofitting them, although wise and perhaps policy in some societies, is called for anywhere. It is an advisory not stipulation, but I could verify that from the orange-on-white book; and obviously to consider if I replace these ones anyway.  Such a valve can readily be given restrictor-spacers to experiment.

I should add that irrespective of locomotive, it has always been my practice to close the blower a little at a time as pressure rises, and at blowing-off to leave it open only just enough to make the fumes go the right way.

On this loco the blower was effective in my tests last week, from only about 20psi on the gauge!

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So essentially. combing advice on here and from my club’s boiler-testers and other engine-owners, first approach is to smooth the flow of steam through the safety-valves without changing the basic design, and some form of choke or opening-restriction on the blower control.

”””’

Another problem I have to sort is the reluctant injector, and one suggestion passed on by a fellow club-member, is to fit a larger steam-valve and pipe. The theory being an injector wants plenty of steam, not just “strong steam”. Volume as well as pressure, or more likely, minimising pipe losses. I must admit that’s new to me but there could be something in it.

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Regarding a club boiler tester thinking you don’t need a SAT because any decent engine-man would close the blower (and damper if fitted)…

That is all very well and of course he should, but it ignores human fallibility such as the driver distracted.

Let’s just say my own Societies (I am in two) would not countenance that sort of nonsense. An incomplete test and record would be wilful negligence potentially voiding the club’s insurance, as well as by which a host club of an event like a rally, could bar track access to a visiting locomotive.

This loco has no WSE either, but I think that is a recent development, after the last time it was tested.

It’s no problem to prepare one though, and using a sample form I have written the required details in the correct order to facilitate the boiler tester transcribing it to a real form.

I don’t have copies of the old MELG code to examine. There may be ones in our club-room, though it’s possible they were thrown away to ensure no-one tried using them.

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With the loco back home, I partially dismantled the two manifold valves to ascertain their types. They need overhauling anyway.

That feeding the injector has a captive spindle created by a flange with its operating thread on its periphery – the same 3/8″ X 32tpi as the rest so very delicate-looking with only two or three full thread turns. Curious way to do it, but it works, albeit with a slower action than I’d like.

The blower-valve, of smaller diameter, is non-captive but has a long thread so needs a lot of unwinding to release. It has a 3/16″ BSW or perhaps 2BA thread, so very small lead, but when I tested the boiler less than half a turn over-drew the fire as I’d observed. A simple restrictor would be an 1/8″ tube between it and the hollow-stay connector.

This captive / non-captive difference is a bit odd, as the turret and valves were clearly made at the same time by the same person.

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The tanks on this engine have an air-gap from the boiler of no less than 1/4″ at narrowest, open all round (no closure plate between the tanks and boiler on their ends or along the top). So I would not think the water would become very warm. Indeed the injector was side-tank fed on the engine’s original form. As it was a portable-track hauler, used at Summer events, the Sun was likely the tanks’ main heater, not the boiler.

Even so the injector on there now had been plumbed for a driving-trolley tank, and this is how I used it.

I know they deal with vastly greater volumes of water, but how do full-size tank locomotives manage, especially the pannier and saddle versions? I have, briefly, driven a full-size narrow gauge saddle-tank locomotive whose injector and feed check-valve are directly on the back-head, and have seen similarly on a vertical-boiler NG engine. On both the injector is expected to lift the water into itself as well.  One of my inherited engineering text-books describes the injector with its example having a single control with very quick-acting thread for both water and steam, boiler-mounted and apparently capable of lifting water from a tank at floor level.

I know injectors do not like water that is too hot, but that is not the only reason for them refusing to inject at times. Yet an injector that needs also pull the water up before pushing it into the boiler will have steam running through it for a very short but appreciable time before the water arrives.

We “cannot scale Nature”, says Received Wisdom – very true, but I can’t help thinking sometimes RW leads to missing the real problem. It’s an intriguing point and I have not seen definitive answers to it.

I am tempted as what was a service turns into restoration to fit this locomotive so its injector (1 now, perhaps 2 in future) has/have the choice of water source, and see what happens.

It’s quite a large injector – 40oz/min – intended to be connected with 1/4″ pipes, but there’d be no harm in fitting a larger, and faster-acting, steam-valve and 5/16″ or 8mm pipes, with 1/4″ for the last little bit into the unions. Apart from aesthetics; but although it should look reasonably “right” this loco is a rather freelance version of a freelance design, not a fine-scale rendition of a specific prototype.

Paul –

I am well aware that “full-size” injectors are more complicated than their miniature versions, and good luck to anyone who tries to make a working exhaust-steam injector for a miniature BR Standard-class locomotive! (I doubt very much it would be feasible and I don’t seriously suggest trying. A “simple” injector of near-prototypical external appearance is a different, and laudable, aim.)

However, they still work in the same way! The split combining-cone is cone and starting valve in one component. That would be very hard to follow reliably in miniature, hence the ball-valve instead.

Some injectors on “full-size” plant had single-piece cones and ball or poppet valves; at least in the smaller, simpler versions. They were probably simpler hence cheaper to manufacture and to service.

A miniature injector should lift water, to a limited extent, but is better with gravity feed as was full-size railway and traction-engine practice anyway, with very few exceptions.

I had raised this to ask if using the tanks to feed the injector on a miniature tank locomotive is quite the Wrong Thing as we are told.

As built, my own loco, a doubled “Juliet”, was used for much of its earlier career with a combined driving / passenger-truck having no water-tank. Although its axle-driven pump would have been the main feeder on busy portable-track events, I do not recall its side-tank fed injector having problems definitely caused by water temperature. Scale was the main difficulty, in our hard water area.

The chapter on problems in D.A.G. Brown’s book on making these devices, is comprehensive but does not mention feed-water being too hot. It covers dimension errors in the device (sometimes, in commercially made ones), scale or dirt (obviously), and air-leaks. These last can be very devious and hard to trace, such as, he explains, flux residue in a soldered joint eventually dissolving to leave a minute air-passage through the joint. Though the more likely course of air-leaks is on flexible tender to locomotive feed-bags consisting of simple rubber or plastic tube pushed onto the pipe ends.

He also details the prototypical Giffard-pattern injector he made for his Manning-Wardle saddle-tank locomotive. I am confident Mr. Brown would have lagged its boiler very well indeed, but such an installation would still be an eye-brow lifter for many.

What I have also picked up from his book is that the 40oz/min injector it sports might be too large (its axle-pump definitely so, for continuous, steady feed). It may repay trying a smaller injector, on the same 1/4″ pipes apart from needing short 3/16″ pipes in the smaller unions. Mr. Brown points to inadequate water, not steam, feed as the main difficulty. In principle it should be possible to use injectors sized to keep a reasonably steady water-level without hogging the steam output.

So while obviously I hope the tanks are not a “free” feed-water heater, just what is the truth about tank v. tender feeding injectors on miniature tank locomotives?  Or does it just potentially swap temperature with air-leaks?

Well, not only not detailed but apparently about Outlook, mainly, but Microsoft’s own none-too-helpful help site revealed other users having problems with Excel after a recent “up-date”.

My PC reached a point that neither Excel nor Word would open at all, even in the proffered “Safe Mode”. Nor did two third-party programmes, though TurboCAD and Alibre still functioned.

Luckily I found a full re-installation repair, and used that. It took over an hour!

This not only unlocked everything. It let me find some lost photos – MS had moved them to OneDrive without telling me. It also allowed me to open the damaged spreadsheet in Safe Mode, re-save it under a new name and copy it to external storage. The message said it was severely damaged so formulas [sic] might not work, but it is a pure index, without any formulae written by me in it. Another spreadsheet that does contain some simple formulae and graphs, still seems to operate properly.

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Regarding safety-valves, closely examining of of mine showed the exit holes in the top are partially eclipsed by the spring, and I wonder if that is a common problem with these.