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Steam Locomotive Driver Counterweight Names

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Steam Locomotive Driver Counterweight Names
Posted by cowcatcherrider on Sunday, April 5, 2020 4:27 PM

 

As a longtime model railroader, you'd think I would know this, but I don't think I do... beyond the following descriptions.  Maybe somebody knows the correct or majority used names or descriptions.  What I'm referring to is basically the shape of driver counterweights.  My mostly photographic viewing reference, for instance is, beginning with c. 1860: the weights seem to be pizza shaped and bolted between the spokes.  Then around the 1880s, they were cast in with square corners.  After that, around 1900 or so to the last, they continued to be cast into the wheel, but were crescent shaped.  So what are these three types called?  Or are there more?

 

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Posted by ndbprr on Monday, April 6, 2020 7:45 AM

I have been in the hobby for 60 years and do not recall anything other then counterweight.  There  are different types of drivers though

 

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Posted by doctorwayne on Monday, April 6, 2020 10:08 AM

As far as I'm aware, they're all known simply as counterweights.

cowcatcherrider
...beginning with c. 1860: the weights seem to be pizza shaped and bolted between the spokes.....

I assume that you meant to add "slice" after pizza...most pizzas are round, and would have covered the driver completely.  The really big ones, though, are (or were) rectangular... haven't seen one in years, though. Smile, Wink & Grin

Wayne

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Posted by cefinkjr on Monday, April 6, 2020 2:02 PM

doctorwayne
I assume that you meant to add "slice" after pizza...most pizzas are round

I have seen square or rectangular pieces of dough, baked with tomato sauce and other "fillings" on them but are they pizzas?  I don't think so. No

Chuck
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Posted by Eric White on Monday, April 6, 2020 3:06 PM

In the Northeast the rectilinear pizzas have thick crusts and are referred to as Sicilian style. The round ones are Neopolitan style, and they should always be cut into triangular pieces, not matter what my new neighbors in Wisconsin may think.

Eric

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Posted by gmpullman on Monday, April 6, 2020 3:07 PM

Most of the documentation I've read involves driver and side-rod design in later "super-power" years where railroads were taking a hard look at reducing reciprocating weight, higher speeds and less damage to trackwork and roadbed.

Along those lines the builders were working with new alloys, roller bearings, fine tuned counterbalancing, better steam control and admission among other engineering considerations.

 Timken_Rods_Fig.1 by Edmund, on Flickr

Here are a few examples of the latest Boxpok driver centers. One design having cavities that could be packed with lead and better balancing.

 Driver_0001_crop by Edmund, on Flickr

 Driver_crop by Edmund, on Flickr

The Scullin Disc center was another development that was having some success at reducing unnecessary balancing problems.

 Driver_0001 by Edmund, on Flickr

I posted pages from a Timken study here regarding lightweight rods and bearings for locomotives in service at over 100 Miles Per Hour for further reading.

Good Luck, Ed

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Posted by OT Dean on Wednesday, April 8, 2020 1:13 AM

cowcatcherrider

 

As a longtime model railroader, you'd think I would know this, but I don't think I do... beyond the following descriptions.  Maybe somebody knows the correct or majority used names or descriptions.  What I'm referring to is basically the shape of driver counterweights.  My mostly photographic viewing reference, for instance is, beginning with c. 1860: the weights seem to be pizza shaped and bolted between the spokes.  Then around the 1880s, they were cast in with square corners.  After that, around 1900 or so to the last, they continued to be cast into the wheel, but were crescent shaped.  So what are these three types called?  Or are there more?

 

 

I've heard the "pizza slice" counterweights called "Segmented," the square-end ones "Square-ended," or just "Square," and the ones with pointed ends are usually called "Crescent Counterweights." the latter two could be mixed, just as pilot wheelsets could be mixed spoked or solid.  (I feel kind of dumb that I never realized the square-end and crescent types were part of the castings, with carefully calculated amonts of lead added inside to counterbalance the various rods and valve cranks.  Stay safe!

Deano

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Posted by cowcatcherrider on Wednesday, April 8, 2020 3:46 PM

Ed,

Thanx for you comprehensive reply... that avoided talk of pizzas.  In Googling, I too ran across info about driver types and complicated math formulas on counterballencing, but nothing specific on counterweight design names.  So I guess for now it shall remain a mystery of no great importance.

Ross - Irvine, Calif.

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Posted by cowcatcherrider on Wednesday, April 8, 2020 3:48 PM

Thanx for you comprehensive reply... that avoided talk of pizzas.  In Googling, as you may have, I ran across info about driver types and complicated math formulas on counterballencing, but nothing specific on counterweight design names.  So I guess for now it shall remain a mystery of no great importance.

Ross - Irvine, Calif.

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Posted by Overmod on Wednesday, April 8, 2020 3:50 PM

I have seen the 'crescent' shaped ones called 'lunes' (for evident reason).  There is a name associated for the 'divided' type (which was popular for high-speed  around the 1880s, I think) but I don't remember it offhand.  I always called the 'square' kind 'box' counterweights.

About the best example of 'counterweight' casting I have seen, for pure casting sophistication, is a comparatively low driver center 'outside' KRM in New Haven, Kentucky.  It clearly shows where weight is saved and where lead would go.

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Posted by cowcatcherrider on Wednesday, June 3, 2020 1:20 PM

Overmod,

I don't check my messages in this forum as often as I should.  Thanx for shedding some light on this (counterweight) issue.

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Posted by Wolf359 on Thursday, June 4, 2020 12:54 PM

OT Dean

 

I've heard the "pizza slice" counterweights called "Segmented," the square-end ones "Square-ended," or just "Square," and the ones with pointed ends are usually called "Crescent Counterweights." the latter two could be mixed, just as pilot wheelsets could be mixed spoked or solid.

 

Deano

 

I've always heard the "pizza slice" counterweights refered to as "bolt-on" counterweights, and the other two types as "square" and "crescent" counterweights as Deano said. I beleive it was fairly common to see "square" and "crescent" counterweights on the same locomotive in the early 1900s. Hear's a link to a photo of a Colorado Midland 2-8-0 with mixed counterweights: https://digital.denverlibrary.org/digital/collection/p15330coll22/id/51090/rec/5

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Posted by dknelson on Thursday, June 4, 2020 1:29 PM

Model Railroader Cyclopedia Vol 1 Steam Locomotives, by Linn Westcott, uses the "segment counterweights" and "crescent counterweights" vocabulary on p. 29 (for an Omaha Road 0-6-0 where photos showed both types).

Out of state Kalmbach staffers, and Eric White is not the only one, all seem to complain about the square or rectangular pizzas that are popular here in Wisconsin (often called "family style" pizzas).  The visible evidence suggests that they are eating plenty of Wisconsin pizza, they just miss the wedge shaped slices of their east coast youths.

Dave Nelson

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Posted by Overmod on Thursday, June 4, 2020 1:33 PM

Note that improvements in patterning and casting would be needed for 'lune' counterweight pockets to make full sense.  Before that, the necessity to have light weight, strong and complete spokes, and strong and 'cracking-resistant' shape between spikes and rim would make bolt-on counterweighting completely divorced from the structural wheel a better choice.  Some of the later spoke centers are, like Phoenix bridges, triumphs of fabrication making up for materials expense.  You can easily see why more indeterminate cast (or even fabricated) disk-type centers caught on so thoroughly in the age of angled cross-balancing and lightweight 100mph rods... 

 
There is a name, and probably a patent history, for those 'split counterweight' types meant for high speed/low augment in the late 1800s, but I don't know it yet ... this is probably an Ed question like the actual history of "Ohio" tender trucks.  The idea was to carry counterweight, including necessary overbalance, as a 'resultant' rather than directly opposite the mass or rods and pin to be balanced.  I have never been too sure this was any better engineering than the telepomp, but that may just be me.

Perhaps interestingly, in the bad old depths of drag-freight emphasis, CB&Q built a locomotive with so much rod mass, inertia and piston thrust that its main couldn't physically hold enough counterweight mass (IIRC this was about 1916).  The solution was to fit additional bob counterweights to the axle, inside the frames, looking a bit like throws for a three-cylinder locomotive.  This would have been relatively nifty in limiting overbalance to the outside masses (where it would act better on reducing yaw or hunting) while keeping actual overbalance mass to a minimum.  Again I do not know what these weights would be 'properly' called.

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Posted by cowcatcherrider on Tuesday, June 23, 2020 1:08 PM

Wow... I'm learning a lot from all the replies.  Thank you all very much.

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