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Building a Live Steam Locomotive

Regarded as a hobby, building, and running, scale model steamers is a much more widespread activity than is generally known to most. That fact lies perhaps in the complexity of the effort, as well as only those getting on in age can remember them plying the rails in their full-size immensity. I am one of those individuals, and have outlined my interest in live steam in another 'thread' here, if I may use the vernacular used over here (I appreciate the term 'topic' used in this Forum!).
By way of introduction, above is the 'madman' responsible for the construction of the hulk behind him, pictured about 3 years into the project, certain identifying 'cosmetics' not yet applied, but the general idea of what it is, and how big it is, can be seen.
Here it is under steam, during late Autumn, part of the trackage I have laid in the pasture adjacent to my shop visible. Just to the left of the tree the switch can be seen, by which the loco exits the spur which leads to the shop, allowing use of the irregularly-shaped 'loop' of track having about 800 feet of length around. The radius of curves is 50 feet; this fact precludes 'backyard' operation of a beast this large. It was running on propane, the bottle being visible behind me. It has not yet been decided whether propane will remain the fuel of choice; if it does, a 'tank-car' will be provided consisting of the LP tank from a fork-lift truck. These are just about proper scale size, and can be concealed as a railroad tanker type car.
The linedrawings above, along with some photographs of the CB&Q 5632, were the sole illustrations available to begin work from. Thus, the term 'scratch-built'. This made it impossible to secure detail information down to the tiniest size, and therefore, to the 'purists', my work is not truly perfect in scale duplication. Decades ago, many railroads offered bluprints of many of their locomotives for sale to the public; these prints are now long-gone, for the most part, making duplication quite difficult.
This class, 0-5, were designed and built beginning in 1940, by the CB&Q Railroad's own shops, in Iowa! Only the boilers and cast parts were purchased by contract. I believe this attests to the incredible technical capability of the railroads. The 0-5 class were very successful locomotives, hauling both freight and passengers. Originally coal-fired, many were converted later to fuel oil, and re-classed 0-5A; 5632 was one of those. It's tender then became a two-tanked liquid fuel carrier: water and oil.
Several months were spent preparing working drawings. To do this, I used the few basic dimensions shown on the linedrawings, and scaled parts' sizes which were not dimensioned. Eager to get my lathe running, what else to make first, if not big wheels? The pic above shows a 9-1/4-inch driver wheel being prepared in the vertical milling machine. The 5632 had what are called 'Box-Pok' wheels; their holes were key-hole shaped. This proved a bit tricky, since everything had to be machined from the solid, no castings whatsoever being used anywhere in the model.
A question was asked regarding my boiler. I thought hard and long about that gnarly problem. The project was begun at a time when my wife & I were living with no steady income, trapped between the years starting when, the Y2K 'disaster' pending, we 'dropped out', so to speak, of the workday rat-race, sold our custom home in Phoenix, Arizona, and used 1/4 of those proceeds to buy a 92-acre spread in the Missouri Ozarks. At that point in time, I had no intention of continuing to 'work for the man' until either pension became available, or I dropped dead. Thus, funds were scarce for such frovolity as locomotive-building. I 'scrounged' as much material as possible, until in 2004, pension became available to me, and certain niceties, like ball bearings, could be purchased! By that time, the 'nest-egg' had been largely depleted by everyday living costs.
I reasoned that the steel tanks used for compressed gases, such as oxygen and nitrous oxide, are very strong, typically carrying 3,000 to 4,000 psi pressure, safe and rugged enough to be transported by ordinary means, and some had just the right diameter to be used as a water boiler! My life-long friend, Charlie, a Metallurgical Engineer, informed me such tanks are mainly made of 4130 steel, a strong, easily-welded alloy. He agreed that 100 psi hot steam would prove no match for their strength. I ran an ad in the newspaper, seeking discarded tanks. I was thus able to secure 'boiler material' almost for free; in fact, a Dentist gave me 2 nitrous oxide tanks!
The pic above shows the sawing off of the end of a tank, a process some had warned me would produce dire consequences, possibly even death! Can you imagine? The 'old wives' tale about cutting into tanks!
The 3 above: The firebox and water compartment above it, about to be joined by arc welding (top).
The firebox joined to the water compartment, with one side remaining to be attached. (center)
The rear of the firebox, showing the opening for fueling. (bottom)
Thickness of the section of steel tank, as well as the firebox plates, can be seen as about 1/4-inch. A critical part here is the so-called 'crown-sheet', on top of which a relatively thin depth of water is exposed to great heat, causing rapid boiling. The crown has a rib welded in place between it's top surface, and the top of the water compartment above, to prevent it's 'bowing' upward under operation. Numerous boiler explosions have been recorded historically in locomotive lore; generally, these resulted from the crown sheet being 'starved' for water, as when attention was not paid to water usage.
At this point I shall retire for the night. I hope my description here moves some to comment! I welcome questions, criticism, even downright disapproval, regarding my work, and hope perhaps it may promote further interest in the 'sport'! impish

No need for disaproval from me! I love reading stuff like this. Wish I had your knowledge and expertise myself and the space to do something myself. Keep up your good work Lovely Loco by the way!

Bookmarked this thread.. I've got a feeling it's going to be right up there with many of the Reader's Cars build threads.
Fantastic stuff!

Nicely written and a proper project. Welcome to PH, you'll like it here

Just.. Wow!

Gentlemen (and Ladies!), I am flattered and humbled by the quick and favorable responses to my toils! I must apologize, therefore, in advance of disappointing detail, since the great bulk of my build information, pics, drawings, notated facts, etc., are back in my shop in Missouri, as my wife & I languish daily away from the cold and disagreeable weather there, for the next 3 months or so, in Arizona. As in any mountainous region, we need only travel 100 miles away from the Colorado River here in Laughlin, Nevada/Bullhead City, Arizona, to experience plenty of snow and cold, should we desire that. Today, it was sunny and 68`(F) here!
I shall, nonetheless, continue ahead with what little I have available to work with. Thank you again! A new Member here is surely made to feel much more welcome, than has been my experience with some of the similar forums based here in the States. impish

Hi Steve, we are very friendly here in the uk Especially when model steam loco's are involved!!

Thought you might like to look at this http://youtu.be/QLGwa5HRk54

Above is the cylinder block and liners. Bore is 3 inches and stroke is 3-1/2 inches. The use of aluminum (aluminium, as I expect is preferred in UK?), in construction throughout is prevalent, not to save weight, as indeed, these machines depend on weight for traction, but rather ease of machining. Where wear surfaces are needed, other materials were employed: aluminum bronze for the pistons and valves, Tobin bronze for the liners. Piston rings are a stock item specified for a certain Briggs & Stratton lawnmower engine! At this point, though tempted, I will refrain from talking about aluminum pistons used in automotive engines: they aren't round (elliptical), have cast or forged-in steel struts within, and the piston pin holes (gudgeon pin!) are bored off-center!
The cylinder block consists of two 3/4' plates separated by a solid block of appropriate length, into which are inserted the ends of the cylinders, which are 1/4'-walled tubes. The liners, bronze, are lightly pressed into the cylinders. Liners have the appropriate passages machined within them to admit steam into and out of the inside of the cylinder liners. The pistons, of course, run within the larger bronze liners. The large rectangular opening in center of the block sits snugly over the chassis side-rails of the loco, being bolted to them. At operating steam pressure, the maximum force applied by the pistons to the connecting rods, and thus absorbed by the block mounting, is about 1,000 lbs. This piston force, of course, alternates back and forth, as the turning effort is applied to the wheels, the design being a double-acting cylinder, as are all steam locomotive cylinders.
Regrettably, I have no pic handy of either a piston, or slide valve, but suffice to say the pistons have 2 rings each, and are only 1/2 inch high (or thick, depending on perspective). The piston rod (analogous to an I.C. connecting rod) is rigidly affixed to the piston, is 5/8' in diameter, type 302 Stainless Steel, and rides in a bronze bushing in the rear cylinder head closure. The valves are piston-type (circular) and spool-shaped, 1-1/2' in diameter, and only 2 inches long. They are placed in motion by a 1/2-inch diameter S/S rod, in fashion similarv to that of the main pistons.
Of much consternation in any live steam application, is the type of 'valve gear' employed, that being the mechanism by which the valves are moved a proper amount at the proper time. 5632 prototype used Baker-type valve gear, a system widely employed in America, but I believe less popularly so in UK. Much drawing board time was spent laying out larger-than-scale plans to determine critical parameters relating to valve function. The valve gear is also responsible for controlling the direction of travel of the beast!
As the big-wheel crank-pin rotates, the big-end of the connecting rod, which is about 17 inches long, forms a continually-changing angle with respect to the pivot-point where it meets the piston pin. This produces very undesirable, but unavoidable, side-forces on the piston and it's pin both, which can cause quick wear of both. A structure in locomotive practice called a 'crosshead' is employed to constrain the piston pin in it's axis of back and forth motion. My scaled-down crosshead uses 4 ball bearings which roll back and forth within rigidly-held grooves. For this reason, the crosshead deviates from the prototype in appearance. Abrasive condition for the purist modellers!
Above is a close-up of the right side in which the cylinder block, cylinder, crosshead, valve gear, eccentric rod (which drives the valve gear), main rod, which is connected to the second drive wheel back from the front, there being 4 drivers per side, and the 'side-rod' which connects all the drivers together so they may turn in unison. Spherical bearings are employed in the main rod small-end and eccentric rod gear-end, the big ends containing ball bearings, as do the side rod connections to the wheels. Additionally, side-rods must be 'jointed' in two places, using hardened steel pins and bushings (bushes, UK?)to allow the suspension of the locomotive to move up and down. Brake shoes may be seen, as well as the 'tear-drop' holes and counterweights of the wheel.
At this point, I am thinking far too quickly and clearly for the time of day, and will submit to a nice glass of home-made wine, cranberry in this case! Thank you for reading! I welcome any and all questions or comments which may come to mind! impish
Edit: Yorkie, thank you for the very nice video which I just found, having completed my post! It is especially nice for us just now, since back at home in our rural location, only dial-up Internet service is available; vids are an impossibility there. Perhaps we should remain here in Arizona! Anyone want to buy a locomotive?

No problem Impish, Here is a link to a most impressive railway In the south east of the uk http://www.google.co.uk/url?sa=t&rct=j&q=r.. About 3 1/2 drive for me.

I would love to see the beautiful engines in person, shown above!
Now, continuing with my 'build':
Not sure just how technical to get here. The view above shows the exhaust nozzle, 'pettycoat', and smokestack (only the very top visible) as they reside within the smokebox, which is attached to the front end of the boiler. Spent steam exhausting from the cylinders exits upward through the nozzle, through the center of the pettycoat, and out through the smokestack. The pettycoat is actually a hollow cavity having tapered walls, in the fashion of a Bernoulli tube; the smokestack is tapered inside, also.
We all know how chimneys work, the hot air and gases rising upwards by the nature of it, through the chimney stack. A locomotive boiler is nothing more than a fancy chimney, but it lies on it's side. Smoke and spent combustion products must be forced through this horizontal chimney, a feat accomplished by the flow of exhaust steam upwards through the pettycoat causing a low-pressure to exist within the smokebox chamber, this then causing an in-rush of fresh air at the rear of the locomotive, into the firebox, where it nourishes the fire, and the resulting gaseous products flow through the many flue-pipes of the boiler, towards it's front end. This effort carries much heat along with the smoke, which is transferred through the relatively thin walls of the flues to the water surrounding them within the boiler, creating steam. Thus, the harder the locomotive 'works', the greater the flow of air to the fire, which is exactly what is needed. As the locomotive coasts in motion with it's throttle closed, little or no fresh air flows to the fire, and it's heating effort drops off. While idle, and not in motion, the fire would eventually die out; thus, a manual means is provided of admitting steam from the boiler directly to the nozzle, bypassing the cylinders, to create 'draft', and keep the fire hot.
Contained also in the smokebox, the 'superheater' coils in carrying steam to the cylinders, increase the steam's temperature above the level which exists in the boiler.
Above is shown the smokebox attached to the boiler, containing the pettycoat structure, without the superheater coils installed. The nozzle was absent in this view, but the smokestack may be seen.
The pic above shows the superheater coils as they reside in front of the boiler proper, with the smokebox outer housing removed. The slender tube reaching forward and curving around about 3/4-turn, is the steam feed line for the manual nozzle operation; the term used is 'steam blower'. As can be seen, the boiler flue pipes are copper.
Here is a view looking into the smokebox from the front of the engine, with the clean-out door swung open.
Above, my scrounging activities again evident, I asked my wife if she had any small, metal container such as various spices are sold in: she came up with the steel paprika box from 'Szeged' Spices, of Hungary, I believe! Properly attached and painted, that little box is now the lubricating oil reservoir for the cylinders! Visible in this view is the brass oil pump, driven by the crosshead motion. The pump delivers a tiny 'squirt' of steam cylinder oil to the inlet of the steam valves, from which it travels down into the cylinders. The rectangular box to which Mr. Szeged is mounted, with it's rectangular viewing-hole, contains the guide mechanism for the valve rod; as usual, this rides on ball bearings. The valve-gear is fairly concisely shown, also.
Next time, I will finish with the construction of the tender. Thank you for looking! impish

I'm rather enjoying this thread Impish, A joy to read :-) I lokve the paprika box!

Not sure just how technical to get here.

Edited by The Excession on Thursday 19th January 09:48

Thanks for posting. I love the subject matter.. I never tire in my fascination of the horizontal chimney.
One of the complications with scaling down logos is the stresses aren't always presented in the same way as the 1:1 scale..did you feel the need to oversized any of the parts?

One of the complications with scaling down logos is the stresses aren't always presented in the same way as the 1:1 scale.. ** This is true! From a practical standpoint, few parts in the model are really stressed very high: more important considerations develop regarding wear of mating surfaces, hence the use of 'frictionless' bearings wherever possible.
did you feel the need to oversized any of the parts?