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Train Legnth v. Tonnage rating v. Drawbar HP?

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  • Member since
    November 2002
  • From: Colorado
  • 4,075 posts
Posted by fwright on Wednesday, December 24, 2008 9:18 AM

It takes a heavy steam locomotive in HO to pull the same train length its prototype could. Light, plastic locomotives don't get there. Removal of weight to fit electronics exacerbates the situation. Speakers need room, and bigger is better for speaker sound. An air tight enclosure is required behind the speaker to prevent losing sound volume and quality to out of phase oscillations. All these make the combination of sound, DCC, modern plastic shell castings, and prototype train lengths incompatible - especially in N scale. Even with lighter car weights, rolling friction of car trucks does not scale linearly.

There is a huge difference between a 2% and a 3.5% grade, especially in N. Typically, the number of cars a model engine can pull is cut in half by a 2% grade - and cut in half again by a 3.5% grade. By the time you get to 5% grades, you are down to 3-4 cars for a good pulling locomotive.

As others have stated, there are likely problems with your proposed scenario. Train lengths up grades don't seem to match estimated current capabilities very well. Given the limited amount of steam locomotives available in N, I would construct a test track to check the actual capabilities of N production locomotives you like. With that knowledge in hand, you can better plan grades, train lengths, and curves to fit measured capabilities. Going the other way (setting grades and train lengths first) will likely meet with problems finding production locomotives with the required capabilities.

my thoughts, your choices

Fred W

  • Member since
    September 2003
  • From: Omaha, NE
  • 10,621 posts
Posted by dehusman on Tuesday, December 23, 2008 11:39 PM

GM@CASPer Centeral
  I am starting fresh.  Finishing the basement, almost no locomotives/rolling stock, no buildings, track anything.  I abandoned HO scale for the operating capabilities of N scale.  I am looking at 1975-1979, freelanced, running coal fired steam and first gen EMDs.  Ruling grade will be 2-3.5% grade, I want to have scenes in the 7-9 ft range meaning many of my sidings will occupy a complete scene, or be split between two scenes.  Does anyone know what steam models will be up to pulling 28 car freights up a 3% grade on a regular basis.  The diesels aren't a concern as they will tipically be run in 3-4 unit sets.  I can doublehead if needed.

Steam died between 1955 and 1959.  So unless you typo'd you are 20 years to late for steam.  By 1975 most 1st generation EMD's were pretty well worn out and the majority of them were traded in on newer hood units.

If your ruling grade is 2.5-3% then you will need to double head steam with pushers.  On those type grades the WM would run as many as 6 or 8 of their huge consolidations.  On those type grades you may need helpers with diesels too. With such a large space why are you going with such heavy grade?  Why not 1.5-2%

Dave H. Painted side goes up. My website : wnbranch.com

  • Member since
    November 2007
  • 2,989 posts
Posted by Railway Man on Tuesday, December 23, 2008 11:16 PM

A D&RGW 3600-class 2-8-8-2, one of the largest and heaviest 2-8-8-2s built, was rated at 1350 tons ascending 3.0%.  That equates to about 20 loaded cars in that era.  A model might do much better, then again, it might not.

RWM

  • Member since
    January 2001
  • From: SE Minnesota
  • 6,845 posts
Posted by jrbernier on Tuesday, December 23, 2008 11:15 PM

  You have quite a list of things you want to do.  First off is that date - 1975-1979?  Maybe you meant 1955-1959?  Steam models pulling 28 car freights up a  3% plus grade may be an issue - even with HO.  The Bachmann Spectrum USRA 2-6-6-2 is available in N, and the USRA 2-8-8-2 is availabe from Walthers/Life-Like.  You are asking a lot for steam engines to handle a 28 car train up winding 3% grades.  I would think that a 3 unit diesel consist will handle that same train just fine.  You are also talking 15"-21" radius curves - With the layout area you are describing, I would try to keep all curves over 22" radius - The pulling ability of your engines will increase from that alone.  The Kato USRA Heavy 2-8-2 is a fine engine, but there has not been a current run as of late.  They do show up at train shows and on eBay at times.  Sound /decoders are available for steam.  Diesels are another issue, and you might have to 'gut' a powered diesel run a 'sound' car in the consist to have sound.  N scale sound decoders have been lagging behind HO, but I see that there seems to be some movement(Like for the Intermountain FP7's).  One of the problems with N scale engiens has been pulling ability, and trying to jam a decoder in them usually reduces the weight for traction.  I seriously looked at N scale(an invested in a lot of N scale engines).  The decoder install issues in the late 1990's finally drove me back into HO.  The decoder  install situation is much better now, but of course everybody wants 'sound' as well!  A freind has built a nice N scale 'Shasta Div' in the 50's.  He also has a good selection of brass 'cab forwards' to power them.

  I have a 20' by 25' space for my HO layout/workshop, and that is a lot of layout for me to build.  And installing sound decoders in the current crop of engines is keeping me busy.  I have 6 steamers and 8 diesels with 'sound'.  3 steam and 6 diesels are user installed sound.

Jim Bernier

Modeling BNSF  and Milwaukee Road in SW Wisconsin

  • Member since
    February 2007
  • 5 posts
Train Legnth v. Tonnage rating v. Drawbar HP?
Posted by GM@CASPer Centeral on Tuesday, December 23, 2008 9:48 PM

I am in the planning stages of a new N scale layout that will hopefully get underway within the next year or so.  I have portions of a 54x25 ft basement to fill.  It shares space with a garage, office, bedroom, and storage room which wil all be built before layout construction can begin.  I will have sections that incorporate timesavers, display shelvs (staging) and the main layout.  I will also have a worstation complete with locomotive, rolling stock, buildings, and scenery stations to keep tools and materials seperated.

 I hope to keep trainlegnths between 22 and 30 cars plus loco(s) and caboose/combine.  I am running a single track, high density main line with radai between 15-21 inches.  I am partial to peco switches (med-large) and will operate with Digitrax Super Cheif.  I hope to have signaling and AI interface.  I plan to have between 200 and 375 ft mainline run.

 I am starting fresh.  Finishing the basement, almost no locomotives/rolling stock, no buildings, track anything.  I abandoned HO scale for the operating capabilities of N scale.  I am looking at 1975-1979, freelanced, running coal fired steam and first gen EMDs.  Ruling grade will be 2-3.5% grade, I want to have scenes in the 7-9 ft range meaning many of my sidings will occupy a complete scene, or be split between two scenes.  Does anyone know what steam models will be up to pulling 28 car freights up a 3% grade on a regular basis.  The diesels aren't a concern as they will tipically be run in 3-4 unit sets.  I can doublehead if needed.

I would like to run steam in the six- or eight-coupled variety with a couple of 2-6-6-2s for heavy work, but what manufacturers do I need to shop for?  Sound is a bonus, but not nescisary.  I would like sound units in the diesels, though, as I probably wont need but 2 units pulling.

ANY help will be greatly appreciated.

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