Model Railroads/Tunnel Shapes.


Dear Charles

Can we Design tunnels without a circular shape?.

Examples - Triangle, Square, Rectangle, Kite, Rhombus etc


Greetings Prashant,

Although I do not have training in the engineering designs of tunnels, I have read some about the strength of various shapes for arches.

I rule out the square and rectangle because of the weight distribution on a horizontal brace.  The use of a kite shape, (if I understand your meaning) might have some useful advantage but has the disadvantages of the loss of use of the bottom part of the shape.

The Rhombus shape is intriging but suffers the same loss of use as the kite.

I believe that the circular shaped tunnel is the best for utilization of space and suitability for overall strength.  I would however investigate adding the pointed arch as in Gothic design as a modification to the top portion.

You must remember that these are my own thoughts and not from an accomplished engineer.

Best Regards

Model Railroads

All Answers

Answers by Expert:

Ask Experts


Charles Campbell


Questions about Icken Trains ( Fred Icken). Also about electrical workings and problems with electro mechanical pinball machines. Charles


Collected pinball machines for 30 + years and do all work myself. Own a collection of Icken trains. Also many Lionel and American Flyer utems.

I subscribe to Clasic Toy Trains and am a charter subscriber.

Electical/electronics training, U.S. NAVY. BBA 1970 University of Oklahoma.

Past/Present Clients
I do not sell any trains only collect so I do no have train clents. I have in the past sold many old electro-mechanical pinball machines and there have been many customers who have alled me back years later to get one fixed. This is an art that you don't find much any more and the commercial shops charge too much to get a machine fixed. I just try to keep them fixed so that they don't disapear ore are discarded.

©2017 All rights reserved.