Re: Calculating Motive Power Requirements

Charles Peck

Big number of variables, Nelson.  Are you looking at reefers with fresh produce rushing to market?
Hoppers full of low value minerals needing the most economical transport?  Great Plains?  Through
the mountains, not around them?  A river valley route?  How long are your sidings?  Lots of short
trains or wait and drag as many carloads as you can through the pass to harbor?   
Yes, there are formula that tell a real railroad that X tons at X miles per hour up X ruling grade will 
need Y horsepower on dry rail. 
That formula fails on models.  You have to look at the profile (real or imagined), what sort of traffic
you choose for your road, and create a realistic loading.  Are you running 10 or 12 car trains?  Four
high horsepower units will look out of place. Unless, of course, you are modeling Saluda.  Running 
thirty cars and want it to look like sixty cars through Tennessee Pass?  OK, three or four units might
look OK there.  
Pick your biggest train and figure what looks right on it.  Then scale down from there.
One mans ideas, not a rule in any sense.
Chuck Peck in FL

On Thu, Aug 13, 2015 at 8:52 PM, 'Nelson Moyer' ku0a@... [STMFC] <STMFC@...> wrote:

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.


Nelson Moyer

Join to automatically receive all group messages.