7th Street Shops - Ma and Pa Balance Post 30

 

Colorado & Southern narrow gauge drag east of Trout Creek Pass challenged by 3 & 4% grades

I set a Delrin truck (Sn3) I'd just built on the track at the top of Trout Creek Pass (Denver, CO layout). As soon as I let go, the truck started and quickly gathered speed (grades 4% to 0). When I finally stopped it, it was coasting toward the 40 foot mark.

"HO Primer" by Linn Westcott published on the early 1960s

 "Arrange a 36" length of straight track on a board so one end of the track is 1" higher than the other. Then lubricate the wheels on your cars. ...and try rolling them on this hill. Some may take a slight nudge to start but, if any car won't pick up speed, it is a candidate for better wheels or trucks." HO Primer 6th edition, page 39.

While determining the traction effort of a locomotive on a controlled test track it seems the results are a bit optimistic to those realized under normal operating conditions of the layout. On the test grade the slope is constant and controlled. There are no curves and, when using a single car to carry all of the weight, only 8 journals boxes have any influence on the test.

On the layout, the same load is distributed over several cars. This increases the number of wheels, axles and bearing points. It also multiplies any adverse conditions that may be found in the track itself by the number of wheels involved. On a layout the track isn't consistent - often intentionally. Some cars may be on different grades while others may be in a curve. Naturally, all of these conditions come down to one factor; friction.

Modern model trucks have been refined to the point that they almost never cause trouble - especially in terms of friction. But if you run vintage or swap meet "treasures" you may need to be more mindful of the trucks. One way to overcome the short fall of practical operation is to lubricate the truck's journals.

Total train tonnage after lubricating the truck journals =  34.25oz (rare slipping)

Nearly all of the cars in the 54" train above did not roll like the Sn3 truck and the initial train test was not acceptable. Even individually, most of the cars did not roll down the 2% grade as well as expected. (The flat car uses Intermountain trucks.) One car did not volunteer to roll at all. 

Other factors to seek out would the inconsistent grades. There can be places where the track dips or bumps slightly and these can show up during a heavy haul. Also check the track gauge, particularly in the curves. Even when within gauge tolerance the rails can bind the wheels slightly. This can effect the pulling effort of the locomotive. A slightly loose gauge in curves is usually better than tight.

With the exception of the flat car, all of the cars are Central Valley Old Timer Series. Central Valley trucks were among the best available in their day. Because they are metal (which helps lower the center of gravity of the car) and they are sprung by the bolster, they are still my favorite HO scale truck. But, they are all metal and they should occasionally be oiled. 

After oiling all of the trucks (I recommend a light machine oil such as La belle) the test results more closely replicated the single car tests. But not quite; one car was still a little problematic.

We've discussed the tangible advantages locomotive balance can have on tractive effort, the nuances of car weight and well rolling trucks. Now let's consider how this information might also enhance the fun in model railroading abstracts.

Yard personnel and conductors of the trains require accurate records and markings of the various equipment as well as the anticipated load weights to manage their traffic. Especially for the local or peddler freights, where from one location to the next the consist frequently changes, it is important to monitor and collate the information in order to manage the day's tasks. Particularly in rugged country, it is important to assess the tonnage against the motive power's ability. This might exceed the useful limits of fun within our railroad's abstract but it is interesting to consider - the purpose of railroads being what they are.

Of course, we, as modelers don't actually move any commodities. This is one of the abstractions of our hobby that assist our enjoyment - without the mess. Yet, for those who like to play the "game" of operation it seems likely that the actual weights and capacities of the models might be incorporated into the evening's scenario - since they do have an actual affect on the operation. Give it some thought, gamers.

In the photo at left, you can see that the tags call out the weight of each car in real values. I'm still debating whether to use these values or some kind of "realistic" coding. Eventually, this information will be applied to the sides of the cars - where the "conductor" can read them.  

The Moore & Moore Lines is a "big" layout folded, spindled and more or less mutilated into a 4.5'x7' "acreage" But it isn't really that big nor is it particularly designed for the operation game. However, it is certainly aligned with the abstractions of  Whim. 

The primary purposes of this layout is to enjoy running trains and telling the tales of the little railroad, associated communities and the inhabitants thereof. But this doctrine of Whim doesn't precluded realism. The trains do run and they do so because the laws of physics still apply. Therefore the observer should expect to see that the folks and goats and cows and whatever else occupies these acres still have their feet firmly planted on solid Terra Foama.

Reality is the backdrop "texture" for this story book layout; very much in the spirit of the late E.L. Moore and his  Elizabeth Valley R.R. Any details that provide substance to its believability is welcomed to make the narrative convincing and entertaining. Thus, the caricaturization of every engine, car and

M&ML Local takes the train over the high bridges above Elizabeth

feature of the line - whether it physically exists or not.

The weights of the cars and the ability of the locomotives to pull them will be incorporated into the narrative in whatever way the opportunity may offer. The ruling grade is 2% and the one and only passing track can hold 3 - 4 cars. And that's the reality of it.