Steam Loco component interconnection diagram

[Trevor Wood 6Participant @trevorwood6]

Hello fellow engineers!

I am building my first loco – a Kennions “Butch” and am reaching the point where I need to start connecting together all the different subsystems / valves / pumps / tanks /gauges  etc. I have been unable to find any info on how all these parts are connected together – ideally I would like to find a schematic diagram. Ive done a web search and have Martin Evans book, but so far haven’t been able to find a “plumbing” diagram.  Does anyone have such a thing, or know a book or reference I could get to explain how it is all connected together?

Any help would be much appreciated, Thanks, Trevor

[noel shelleyParticipant @noelshelley55608]

Hi Trevor, I have a “butch” in 5″ and all the drawings. There isn’t a pipe plan as such that I know of, and not all were identical, ie, not as to the drawings = modified.

I will answer specific questions as best I can. What do you need to know ? Send me a private message and I can give you my contact details. Where abouts are you ? Best wishes.  Noel.

[MichaelRParticipant @michaelr]

I think you will find that connecting valves to pumps, clacks, gauges, tanks, which are basically fixed points it is up to the builder to route the connecting pipe work in a neat and practical route, have a look at some pictures of various models of Butch on the internet and you will get the general idea of what is required, especially in the back head area.

MichaelR

[Nigel Graham 2Participant @nigelgraham2]

The majority of the auxiliaries are independent from each other and do not really need a circuit-diagram… which is why there isn’t one.

As Michael says, fitting the plumbing is largely a matter of finding the neatest and most practical route for each pipe, and some fittings have only one pipe anyway.

 

Some general points:

Layout: As far as possible, straight runs or parallel to surfaces like boiler flanks, between smooth bends and the connections.  Injectors in particular prefer as few sharp bends including elbows as possible, in their supply and delivery pipes, as such obstancles are flow resistances.

 

Pipe bending:

The bend radius should not be less than 3 X the pipe diameter, and is best created using a pipe-bending too; but be aware that some inch-based diameters do not fit benders with metric formers very well.

I found the commonly-available commercial benders with pliers-like action, is fine on 3/16″ (fractionally <5mm) and 1/8″ (fractionally > 3mm) pipe; but can distort 1/4″ pipe, too much >6mm for the former’s grooves.

Much tighter bends need elbows, but unfortunately for anything below 5/16″ (8mm, a “microbore” central-heating system size) the fittings are readily available via model-engineering suppliers only in male-threaded, union-fitting forms. Other versions might be available but from suppliers to other trades.

If you need alter a bend in copper pipe, it is best to anneal the pipe before straightening it for re-bending.  I “stroke” the annealed pipe straight by hand as much as possible, then very gently use a vice with smooth jaws to press the last wiggles out without flattening it.

Similarly with the preliminary straightening of pipe bought in flat coils, though if handled carefully that will not need annealing.

Though I have not often used this myself it is worth preparing a template for each pipe with stiff steel wire, as far as possible mimicking the intended bend dimensions in it. This not only gives a guide to the pipe’s shape, it also helps find the best route past obstructions.

 

Unions and other soldered joints:

Use low melting-point silver-solder or high m.p. leaded solder (e.g. ‘Comsol’) for joints handling steam at boiler pressure and temperature.

Low-temperature, low pressure joints (cold water, air), can use plumbers’ soft-solder.

 

What is connected where? At simplest –

Pressure-gauge: single pipe from the manifold (aka turret) or its own boiler bush. No intervening valve.

Water-gauge: single, small-bore drain from its blow-down valve to below the footplate.

Blower usually via hollow boiler stay: one pipe from steam-valve to stay bush; one pipe from stay outlet to blower.

Injector (each) – three separate pipes: Cold water from tank via control valve to injector inlet. Some injectors might be connected directly to the water-valve outlet, using a short, threaded pipe-nipple. Steam from control-valves on manifold to injector’s steam inlet. Delivery to dedicated clack-valve on boiler shell. The joints in the water and steam feeds must be fully leakproof. If not, they will draw in air, preventing the injector from working properly.

Mechanical pump driven by an eccentric or from the crosshead: Cold water inlet pipe from tank(s). Delivery to clack-valve on boiler, has a Tee-piece to the bypass valve whose own outlet is pipeed back to the tank.

Hand-pump: usually hidden inside one tank on a side-tank loco, or in the tender or driving-truck tank; and using a single pipe to the boiler clack-valve. It can share the mechanical pump’s clack-valve. I would fit an extra non-return valve close to the necessary tee-piece so the mechanical pump does not try to push water back towards the hand-pump.

 

On tank locomotives: a generously-sized balance-pipe connects the two side-tanks or the legs of a saddle tank, to equalise the water level. The mechanical pump might draw water from this balance-pipe, which also can have a tank drain valve at its lowest point (ensuring the discharge is clear of any components.)

 

Pipes passing through tank walls to continue beyond use a bulkhead union. Use fibre or copper washers and sealant on its threads and flanges.

 

Connections to tenders/ driving-trucks:

Locomotives using either a prototypical tender or a dedicated driving-truck holding an auxiliary water-tank, are connected to that by short rubber hoses quaintly called “feed bags”. One from a hand-pump obviously needs withstand the feed pressure, somewhat above maximum boiler pressure. A feed-bag to an injector needs air-tight connection, as even a very slight aspiration through a leak insufficient for water to escape can upset the injector.

+++

A footnote – Vacuum-brakes (if fitted):

Ejector: steam pipe from a stop-valve on the manifold, another of the same diameter from the brake-application valve; then a significantly larger pipe from ejector outlet to an elbow that enters the side of the smokebox. In his book on making injectors, D.A.G. Brown suggests pointing this elbow’s exit (by a stub of pipe) into the petticoat pipe to act as a gentle blower. Since in operation the ejector stays on, it can thus save steam. The effect should be only just sufficient to maintain the draughting when the regulator is closed.

The application-valve has a second connection, that for the train-pipe, but the “brakes on” air is admitted via a hole in the valve itself. This port should be fitted with a strainer to keep dust out.

Obviously all connections on a vacuum-brake system must be air-tight.

 

 

[noel shelleyParticipant @noelshelley55608]

Copper endfed elbows are readily available for 1/4″ or 6mm from the far east eg the net.  I used them on the link pipes for the side tanks.  Noel.

[Trevor Wood 6Participant @trevorwood6]

Hi All, thanks for the very detailed replies…. lots of stuff to take on board….I’m still learning what all the different components do!

best regards

Trevor

[Charles LamontParticipant @charleslamont71117]

Additionally, the pipe to the pressure gauge should be a U-tube or coil, to act as a condenser so that the gauge works on water, not steam.

[Nigel Graham 2Participant @nigelgraham2]

Noel –

Thanks for that tip. I suppose people like refridgeration fitters would use them.

The 8mm and 10mm pipe and fittings are available from builders’ / DIY suppliers, and indeed I soldered brass sleeves into an 8mm elbow to make a 1/4″ to 1/4″ elbow, only recently. It is tidy and looks right, but that is secondary as the application is purely functional and the fitting hidden. It is though, far neater than the awkwardly reverse-curved single pipe I’d tried first.

 

Charles –

Yes, good point I’d missed. Thankyou.

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