View single post by oztrainz
 Posted: Thu Sep 1st, 2016 01:19 am
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oztrainz



Joined: Wed Apr 10th, 2013
Location: Unanderra, Australia
Posts: 972
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Hi Helmut and and all,
I am going to be a very brave person and modify Harold's reply to read -"On30 narrow-gauge equipment is about the same physical size a S-scale standard gauge equipment"

Harold - is your website still still up? Your Introduction to On30 modelling was one of the better ones on the web that I have seen.

For Helmut - some real world guidance
There is an often quoted (and far more often misquoted) "design rule" that width of rolling stock should not exceed 3x gauge on width because of stability. So this would limit 30" gauge to 90" or 7'6" wide and standard gauge equipment to 14' wide. So going by this "rule", if all other dimensions are in proportion, then narrow gauge equipment should always be much smaller than narrow-gauge equipment.

In reality this "rule" is no more than a rough guideline at best. If you want to see this "rule" shattered for 2' narrow gauge equipment, can I point you to my photos and descriptions at http://www.freerails.com/view_topic.php?id=7230&forum_id=3&highlight=Tully

Also humans do not scale well. Even if the size of a locomotive decreases the amount of volume that is required by the crew in the cab remains relatively constant. Underground mining locomotives are probably the exception to this because the cab area is designed for minimum height, often at the expense of operator comfort. This is one of the reasons why the cabs "look too big" on the smaller narrow gauge locomotives. For freight and passenger cars - Remember you have to fit the humans in. So things like doors and internal heights have to be scaled to ensure you can fit in the passengers and workers. You cannot just take a standard gauge car and hit it with a "shrink ray" that shrinks all dimensions uniformly. I doesn't and can't work that way.

The real benefit of narrow gauge railways was that because of their overall smaller equipment size in general, they were able to fit around tighter curves. In hilly areas using this equipment, it was possible to fit around the side of the ridges rather than having to build trestles to jump the valleys or build tunnels to go through the ridges. Also the size of any benches that had to cut into the side of the hills was significantly narrower as well. This minimised the construction costs for a narrow gauge railway when compared to a standard gauge railway through the same geography, but left you with on-going transshipment costs if the loads from you narrow gauge railway had to be transferred to standard gauge tracks for on-forwarding elsewhere by standard gauge rails. For an isolated system it really doesn't matter how far apart the rails are, just as long as the locomotives and wagons can handle the haulage job.

Remember here, in the days of the horse and cart with unsealed roads, if you wanted to move a significant amount of "stuff" reliably over distances of greater than a few miles, it really was a railway or "no way" at all. In general then also labour was relatively cheap and the transshipment costs were offset by the vastly cheaper construction costs for narrow gauge track than for standard gauge tracks.

Let's have a look at a real 30" gauge railway. Have a look at the rolling stock in the first posting at http://www.freerails.com/view_topic.php?id=7053&forum_id=20&highlight=Puffing+Billy The locomotive is a 2-6-2 side tank and the wagons were built on a common chassis of about 25' long. These were designed to go around a 2 chain radius (132') curves. These locomotives and their tracks were limited to 20 mph on the straight and down to 5 mph on the tightest curves.

In model form, these locomotives are available from Haskell (see http://haskellco.net/0n30puffingbillyNA.html and will go around 24" radius curves, where the prototype needed 33' inches radius. Of the Bachmann On30 range most of the locomotives are designed to go around 18" radius. The Forney needs a wider radius because of its long rear overhang. They might not look real pretty but they will handle the curves and stay coupled to their consists. We tend to bend our model trains around way tighter curves that the prototype did to fit them into our available space.

I hope that this will give you some guidelines for all things narrow gauge.



____________________
Regards,
John Garaty
Unanderra in oz
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