Engine vs Train Length

Our operating group typically assigns one locomotive to approximately eight cars. A sixteen car train will usually have two locomotives and sometimes even three. On a prototype railroad operating in non-mountainous country, this number is usually much higher; say one locomotive for every thirty cars or sometimes even more. It really depends on the tonnage. In a model, however, tonnage is not a factor in the same sense as on the prototype. On a model, once the train is long enough to extend beyond your field of vision, it makes no difference if it is sixteen cars or a hundred and sixteen. You can't see both ends at once. Therefore you can use the same number of locomotives that your prototype usually used even though your trains are not actually as long.

OK. So much for aesthetics. From a purely mechanical engineering point of view, an Athearn HO scale F3 should have no difficulty whatever pulling eight freight cars; even eight brass cars. If you are using Intermountain or similar plastic cars with delrin journals and steel axles, that same F3 should easily pull 25 - 30 cars on straight, level track.

...................F>

In my opinion, if you want this to represent a "whole" train (it seems we always have to scale down for our layouts), I would consider and A/B combination. Early F units were often used in sets (A/B, A/B/A, A/B/B/A) to haul trains.

Of course -- on the prototype -- a singe F3 could handle eight refers on just about any grade, but the A/B combination gives a model train that impression of high-speed service which was a hallmark of moving produce across America by rail.

Thanks F> and Mark ...

I will try to budget an F3 A/B combination for this PFE consist.

Your input helps a lot. I'm trying to make choices that are reasonable at the very least. My goal is to model within an acceptable range of decisions based loosely on prototype activity even though we're creating a fictitious layout.

Most Appreciated!!! Matt

The group I belong to uses the rule that one drive wheel pulls one car, so an F3 would be allowed 8 cars, and an SD9 could haul 12. We have a very long grade that's at about 2.5%, with nearly continuous curvature at about 48" radius. Seems to work pretty well.

- ken

On Sat, 30 Aug 2003 11:28:48 UTC, Matt & Kathleen Brennan wrote: 2000

I too would recommend an A/B or A/A. Having grown up in PFE country it boggles my mind to consider an eight car train of reefers. That's about the pickup from one packing house. Oh well, we must compress.

The Engineers Handbook" by AlcoGE (circa late 1940's) using an Alco GE

Steve Lynch

Jim Hediger, senior editor at Model Railroader magazine, discussed this subject on-line in this week's "MR Express" (September 3, 2003). He assigns locomotives in a similar fashion, using two cars per locomotive axle with adjustments if the engines are GP-38s (2,000-hp) instead of his more standard GP/SD-40 (3,000-hp).