This information is typically found in the Employee Time Table of the prototype. Since it completely depends on the ruling grade, it varies for each segment of a railroad.
From: STMFC@... [STMFC@...]
Sent: Thursday, August 13, 2015 7:52 PM
Subject: [STMFC] Calculating Motive Power Requirements
I’d like to assign motive power based upon tonnage of freight trains. What is the relationship between h.p. and tonnage? Is there a formula used by yardmasters or roundhouse foreman? I know of at least one club that does this, and perhaps some other operators do this as well.