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Model Railroads/Modeling a Single Train running on three tracks.


QUESTION: Dear Frank

Will there be advantages in modeling a train running on three tracks instead of two tracks ?.

I Feel the advantage would be carrying more people capacity for a compromise of Train manufacturing design and additional cost incurred for the same.

Awaiting your reply,

Thanks & Regards,
Prashant S Akerkar

ANSWER: Do you mean running on three rails instead of three tracks?  There would be no advantage of using three rails instead of two. To carry heavier trains (in a historical sense) the size (or weight) of each rail is increased.  One hundred years ago rails weighed about 40 lbs per yard and now in America rails can weigh as much as 155 lbs per yard. At times you will see three or four rails instead of two, however in these cases the train is using only two of the rails to support the wheels, the other rails are electrified to supply electricity for propulsion of the train. London's Underground system uses 4 rails, two to carry the train on its wheels and two to supply power to the train (at 650 volts DC#, one rail being positive and one rail being negative.  The former Southern Region of British Rail used three rails, two as supporting the wheels #called running rails) and one to supply propulsion electricity, the return of the propulsion power was through the running rails.
In fact there have been monorails where the train ran on only one rail. Most famous monorails were the Ballybunnion & Listowell Railway in Ireland and the Wuppertal Suspended Railway in Germany.  Some systems, not the suspended systems. needed a large gyroscope mechanism for balance.  I believe there was a monorail system in India.  Here is a link:

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Train running on two rails
Train running on two r  
QUESTION: Dear Frank

Thank you.

As attached the figure/image, this are my inputs for the design model.

All Trains run on two rails. Now the same train will be running on three rails.

Merits : Length and Height of the train remains the same, adding a new
rail 3 for the single train will result in increase of train width. Now the Load (People, Luggage) carrying capacity will increase. i.e. More People
can commute / travel in the train.

Demerits : Manufacturing cost = Raw Materials cost + Labour cost. Manufacturing cost for the New Train construction to run on three rails will increase.

Awaiting your reply,

Thanks & Regards,
Prashant S Akerkar

Sorry.  Your ideas on building trains to run on three rails is totally unfeasible.
1. The trains will not be able to interchange at all with existing two rail trains.  Interchangeability is one of the major benefits of railways in the first place.
There was in Britain a major railway, the Great Western Railway. that ran on a wider gauge of 7 ft. 01/4 ins. instead of the standard gauge of 4 ft. 81/2 ins.  It ran this way from 1833-1892 and had to spend millions of pounds in 1892 converting all its tracks, locomotives and cars to the narrower gauge, so that it could interchange goods and people rather than having to totally unload one train and reload to another train on the narrower gauge so that the passengers and goods could complete the journey.
2. The width of any train is the main component cost  of building a railway.  Increasing the width of the train dramatically increases the cost of the right-of way, purchase price of the required right-of way and the overall cost of construction.  Why do you think that newer railways are constructed based on dimensions of trains built 100 years ago.  Railway builders are not stupid.  They stay with well established rules of purchase and construction.  Wider rails means larger tunnels, larger bridges, larger embankments, bigger areas for infrastructure such as stations, sheds etc.  To carry heavier loads it only requires a heavier rail to support the extra weight, not 3 rails.  You must be dreaming!

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Frank Edgcombe


I CAN NOT DIAGNOSE equipment problems or ESTIMATE DOLLAR VALUES of your equipment, by email. I have been active in model railroading for forty years. I can answer, or find answers, to questions on most aspects of model trains, railroad equipment or buildings. I have a good knowledge of prototype railroads. I have been employed by five model railroad equipment manufacturers/suppliers and worked for a prototype railroad. I have served, twice, as the president of a local model railroad club. I have been employed as a Reference Librarian, at a university, for the last fifteen years and am used to tracking down resources for patrons.

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