How it started:

After a period of calculating valve gears in MS Excel, many years ago I did some successful quick troubleshooting for a small 600 mm gauge steam loco's valve gear that was performing very poorly.
We measured the piston and valve positions in 4 steps, I drew an Excel diagram ellipse, extracted the proportional part of valve piston movement, calculated the new dimension of a lever bearing position via the rule of three. All this was done within about two hours. Then the loco's owner made two new levers (some kind of combination lever, for Hackworth valve gear) from flat steel, and the loco got back its power like in new state, or even more.

Now I own a valve gear simulation software with optional semi-automatic pre-optimization since more than 15 years, and now also with an additional highly flexible new solver tool on top, which allows me to rapidly simulate and analyze your Walschaerts valve gear (other types currently to be modeled in MS Excel, or to be newly implemented in my software) and find the point to be modified, possibly even starting from a photo and some measured coordinates of piston and valve position.


What we offer: Valve gear remote troubleshooting!

There are two options how remote troubleshooting can be started:

• Option #1 Valve Gear Troubleshooting by diagram:
  A valve event diagram with relative X-Y coordinates is taken by the operating crew moving the steam locomotive step by step and measuring the piston position and according valve piston position for each step, for certain degrees of cylinder filling. For this, outside reference points are sufficient, so no cylinder needs to be opened.

• Option #2 Valve Gear Troubleshooting by geometry:
  A valve event diagram is created by our software, based on valve gear dimensions measured and entered by the operating crew. A suitable slide center position is initially assumed (Y coordinate origin in the slide diagram). This option allows us to massively reduce our workload and offer extremely competitive pricing.

Further steps:

• We check whether the diagrams look good or the valve gear should be modified.

• If the diagrams look good (but still without an absolutely fixed diagram origin), the reason for bad valve events must be looked for in the valve piston environment or setting (Y offset in the slide diagram).

• If the diagrams do not look good, the valve events are compared to an optimal version of the valve gear with ideal valve events, optimized by our software. This comparison shows which parts of the valve gear to modify and how.

How easy it already could be:

At the beginning of this year, the owner of a 15" gauge steam loco for a fun park asked for access to my valve gear design program to check his loco's valve gear.
He modeled the current kinematic skeleton dimensions and later on asked me for advice.
I roughly modeled a version with automatically pre-optimized dimensions and noticed soon that my angle between the main pin and the eccentric crank pin was nearly an exact mirror image to his one. So I told him to check if his drive axle could be mounted in wrong orientation... and he confirmed!


There are very different reasons why someone asked for support, but our highly efficient software allows us to concentrate on the overall image of valve gear behaviour instead of loosing lots of time by fiddling with detail parameters. So I am optimistic that we can help out in very most of all cases with highest efficiency.


I really would appreciate to support you via remote troubleshooting to help you getting an excellently working valve gear.

If you know any steam locomotive operator needing such support, you are welcome to forward the above offer and website link.

I possibly can offer really interesting conditions for acquiring a first standard gauge reference!

This is a really interesting software analysis, and I think it is a potentially helpful tool in interpreting and explaining steam locomotive functioning and maintenance. Can you simulate a steam locomotive that is out of square? This would add a quantitative and visual dimension to a mechanical state that can be heard clearly in contrast to a locomotive that is in square?

I never read an explanation for the English expression "out of square", but I think that you mean a layout with or without a horizontal eccentric rod. If not, please update me. (?)
My software of course can simulate that, and it can simulate any dimension based on a Walschaerts valve gear structure that is able to do a full rotation. One even can use dimensions that do not let it look like a Walschaerts valve gear ;-)

My understanding of "Out of Square" would translate to poorly timed.

An in square locomotive would have the chuffs in a steady, even best. Such as one quarter time from music.

An out of square would have the chuffs repeating in a more random pattern. Such as Chuffchuff, chuff - pause - chuff.

Brian

Thank you for your explanation. OK, now it seems obvious to me too ;-)
So my above answer contained the answer to Thomas' question.

I am still open for a first standard gauge reference, so if anybody knows someone interested at this time, you are invited to contact me!

I would call that 'out of time'. Out of square is when the engine has lost quarter, so the exhaust events may be regular, but syncopated -- chuff-chuff, chuff-chuff, etc. like the 'double licks' on a good simple articulated with the two engines out of phase.

With all due respect to the engineering genius of Mr Ellsworth, the musical term "syncopation" means a rhythm which is irregular, which deviates or differs from the steady pulse which corresponds to the numerator of the fraction expressing the time signature of a given musical phrase. A regular old steam engine is said to be 'square' when the exhaust beats are not only steady but they are even in their volume. The time signature would be 4/4, equaling "chuff chuff chuff chuff" per each revolution of the drivers. If any exhaust beat occurs early or late within this grouping, then the rhythm is syncopated. If any beat is louder or softer than the others, the engine may be in time, but is still out of square.

A three cylinder compound will chug in 6/8 time, rather than 4/4, as in chuff chuff chuff chuff chuff chuff per each revolution. When you begin to hear jazzy sounding patterns such as two groups of three exhaust beats per revolution, or three groupings of two, especially with some beats accented or diminished, that engine is out of square.

Whether an articulated locomotive has it's two engines either in sync or out of sync with each other, the squareness of their engines is evaluated separately --- in other words even when their exhaust patterns do not happen simultaneously, both engines may be perfectly square.... or maybe only one is, or maybe they're both out of time. It just depends.

[quote="Overmod"[/quote] I would call that 'out of time'. Out of square is when the engine has lost quarter [/quote]

Let's say the drivers/crankpins are on quarter, so the pistons all make their power strokes so there is one every 90 degrees. That engine is in time. However if this engine's valve gear is not adjusted evenly, the back pressure could be uneven for those properly timed power strokes, resulting in uneven exhaust beats = the engine is not square, even though it is in time. Uneven back pressure means that piston thrust is correspondingly uneven throughout the power cycle.

-I'm specifically discriminating regular, but unequal-sounding beats from irregularly-timed beats. An engine with 'square' exhaust has regular timing, whatever the timbre or length of the resulting exhaust events.

Someone in Trains magazine noted that many C&O locomotives had a peculiar sound on every fourth exhaust event, even when square -- they described the result as 'chow-chow-chow-wheep, chow-chow-chow-wheep'.

It is true that even if the engine is perfectly in quarter as far as the pistons are concerned, a defective valve or setting at exhaust will throw off the aural rhythm of the exhaust, and that would produce a sort of 'unsquare dance' (to quote elsewhere in modern music!)

The 'double licks' was Ed King's metaphor for the sound of the N&W As, which had separate exhaust tracting for the two engines. Very often when these were working, the effect was akin to jazz drumming, with equal-sounding chuffs now coming in closely-spaced groups of two. But each engine's beats would be foursquare if you could hear them separately...

Agreed. As an (unknown) jazz drummer myself, I am especially reminded of Gene Krupa and those who built on his style, by the sound of the three cylinder express locomotives in Germany. They do indeed "swing" better when they are a bit "unsquare" (think Dave Brubek). Just because an engine sounds a little jazzy doesn't mean it won't pull a train or perform acceptably well, although it's designers, builders, and mechanics are always aiming for perfect squareness. Sometimes fixing something is simply more trouble than it's worth... As my teachers so often told me, "You can't MAKE it swing. You have to LET it swing".

I suppose I could add that when a mallet is working in compound mode, you only hear the exhaust of the low pressure engine...

Double headed worn out Garratts hauling long ore trains up a mountain on slippery rail?

Don't know if Brubeck could accomplish that........ but I'd like to hear a try at it. I used a tape of Unsquare Dance as set strike music after dance concerts in a former life and it made the dancers nuts.

Dave, I suppose that we're drifting OT, but the dancers in Greek or Arabic type clubs can indeed swing in odd time signatures, 5, 7, or 11.

Steve Gadd told me a joke about a drummer in such an establishment who was being canned because he couldn't emphasize the 5th or 7th beats on his snare drum. In almost all Western dance music other than waltzes, the backbeat is played on the second and fourth beats, and when played with extreme emphasis, this is called "Fatback".

I can't think of any steam locomotives which would have an exhaust in an odd time signature other than derivatives of 3.

To continue just a little bit further down a rathole, I can think of two examples of musical alliteration in jazz inspired by steam locomotives: The first is "K4 Pacific", by Baritone Sax player Gerry Mulligan. The second is by Wynton Marsallis, which I have not heard and for which I cannot provide specific information, but it was brought to my attention by my bosses at Ferrovias Guatemala about 20 years ago. I bet somebody on this forum is familiar with it...

And in Rock there is "Train Time", a duet for harp and drums by Cream.

So thanks to all for your concentration ;-) ;-) ;-)