# What scale IS the Roundhouse Sandy River No.24?



## Gary Woolard (Jan 2, 2008)

Title of this thread pretty much says it all, but here's the back-story.

I was steaming my 'new' No.24 at Eric's last month (see Spring Steamup on the Saugus Highline) in front of a consist loaned by Peter Ronney. Peter really liked the look of the train, noting that the size of the Roundhouse engine didn't overwhelm the cars -- which were pretty much, I believe, of the 'pre-Spectrum' Bachmann type, usually described as being 1:22 or so?

Roundhouse says the prototype engine was 46 or 47 feet long (I forget which). The length of my model , tender included, is 27 inches coupler to coupler. A bit of arithmetic tells me that Roundhouse's 47 feet could not have included the tender... but the engine is currently boxed in my mother's garage. (I'm running out of room, 'nuff said!)

It only complicates things to note that No.24 was a two-foot gauge engine, and that Roundhouse's model of it is available in two gauges; 32 mm to represent 2 feet, or the more common in America 45 mm. So i won't mention it.

Bottom line, same as the title -- What scale IS the Roundhouse Sandy River No.24?

TIA,


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## Pete Thornton (Jan 2, 2008)

Gary,
Most UK large scale locomotives are built to 1:19th scale, which is 16mm:ft, to run on 32mm gauge (gauge 0) track representing 2' prototypes. Roundhouse likes to model outside-frame locos (like SR&RL #24) as then they can fit the frames a little wider and move the wheels out to our 45mm gauge (gauge 1.) Two models to sell for the cost of making one. 

Consequently, your #24 is close in scale to the Bachmann 1:22.5 cars, but the wrong gauge. For the correct gauge, the model would have to be 7/8n2 scale, (1:13.7 models on 2' gauge track.) Then it would be HUGE.


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## Phippsburg Eric (Jan 10, 2008)

Mine fits well with my 1:20 scale Maine Narrow Gauge stock I do not have any accurate dimensions of the original and haven't measured the model to check scale.


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## Scottychaos (Jan 2, 2008)

Its 1/19 scale.
As Pete said, thats a common scale for 2-foot modeling in England.

Models that are meant to be 3-foot gauge are modeled in 1/20.3 scale, because that matches 3-foot gauge on 45mm track.

Models that are meant to be 2-foot gauge are modeled in 1/19 scale, because that matches 2-foot gauge on 32mm track. 
Its slightly off for 3-foot gauge on 45mm track (working out to 33.66" instead of 36") but the main focus of 1/19 scale is 2-foot gauge, 
not 3-foot, so being slightly off for 3-foot gauge is considered "close enough"..

If you run it on 45mm track its (almost) 3-foot gauge in 1/19 scale.
If you run it on 32mm track its (exactly) 2-foot gauge in 1/19 scale.

(and before someone questions "exactly 2-foot"..2-foot gauge should actually be 32.08421052631579 mm in 1/19 scale..
I dont think anyone needs to be concerned about 1/10th of a millimeter..so I think the use of "exactly" is justified!) 

Scot


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## HeliconSteamer (Jan 2, 2008)

Sandy River 24 is not modeled at 16mm scale IIRC... Somehow, I want to say that the consensus I heard was somewhere in the neighborhood of 1:21. The subject was discussed at length on a forum, but I cannot recall which forum it was.


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## Steve S. (Jan 2, 2008)

Years ago when I received my 24 I called Roundhouse and asked them what scale the engine is. They were not sure themselves. They said that it is a freelance design from the original engine and would probably be around 1/20 scale or so, but the answer was not definitive. Always has been one of my favorite engines.


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## Scottychaos (Jan 2, 2008)

I just checked model measurements compared to prototype measurements.
The length is a bit short.
Width is exact for 1/19 scale.
and height is slightly short.

Roundhouse might have made it slightly short for ease of going around curves.
But roundhouse makes a lot of 16mm 1/19 scale models..there is no reason to believe this one is not 1/19 scale as well..with perhaps some prototype dimensions that arent exact.

Scot


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## Larry Green (Jan 2, 2008)

When I rebuilt my RH 24 into Belden Falls #12, I did considerable checking of prototype drawings of small 3-foot locomotives. Most dimensions of the model were correct or very close for a small locomotive modeled in 1:20, as I was doing; the cab was the correct size but set too low, so I raised it a scale 10 inches. The stack was raised to suit. The tender was a problem; it was much too low. this was solved by adding larger wheels and coalboards.

Point is: the #24, as modeled by RH, seems to be somewhat of a mystery engine when it comes to scale. Mine looks good pulling a string of 1:24 Delton hoppers, and equally so with a string of 1:20 AMS or Spectrum cars.

Larry


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## Scottychaos (Jan 2, 2008)

Yep, here is the explanation of why its slightly short..from the Roundhouse #24 page:



> Although measuring 28" (700mm) long, it will still negotiate track down to 600mm (2') radius, thus allowing operation on all LGB track.


they made it a bit short on purpose, because of model railroad curves..So the length dimension cant be used to determine its scale..
and if you try to use its length compared to the prototype, you will get a false reading.
which is probably where the confusion about its true scale comes from.
Im 99% convinced its 1/19 scale..the history of other Roundhouse models, and other dimensions on the model, support that theory.

Scot


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## seadawg (Jan 2, 2008)

From what I can recall, the folks at "Northeast Model Products" make 'Maine 2 foot gauge' coaches and combines that were meant to go with the SRRL Roundhouse loco. Notice I said "From what I can recall..."

But like many folks say, it's your railroad. So if you wanted to, you could pull some 1/29 double-stack high cubes!! As far as I'm concerned I like to pull stuff that looks good and is somewhat correct, not necessarily down to the rivet, but at least the correct (or close) number of windows and axles, etc.


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## BigRedOne (Dec 13, 2012)

Aren't Roundhouse mostly modular, with the same components used on many of the models?

That would suggest they took their component set, and said, "what can we build in US prototype with these parts, which is close enough?"


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