Classic Trains Article, Winter 2010, Pages 80-81 - Weight, Adhesion, Tractive Effort And Speed

In some of the Frisco books, Collias' Frisco Power for one, sometimes the engine horsepower is mentioned.

This includes the 4300s, 4400s, 1500s, 1060s to name some.

Is there any correlation between horsepower and tractive effort?

Tom G.

 

On the attachment, I have included Cole's Formula for TE and the PLAN Formula for HP.

You will note that they share certain variables, but ultimately we might say that HP is the rate at which TE is applied.

In some cases, there is a good correlation between TE and HP, such as with the 4300s.

On the other hand the Mallets, which could produce a TE of 100,000 lbs when starting as a simple machine, could not approach the HP of a 4300.

When speaking of steam locomotives and HP, one must always include the speed at which that HP is produced. Unfortunately, Stagner did not give this in his book.

The attachment includes a qualitative graph, which plots TE and HP against speed for a given steam locomotive.

I love this text.

http://books.google.com/books?id=ms...&resnum=3&ved=0CBEQ6AEwAg#v=onepage&q&f=false