Shipments Versus Car Roles

The original design of my CFS program used the notion of a Shipment, which implemented the basic idea of a shipper sending a load of something to a receiver, much as one would expect. The starting and ending tracks could be either in the modelled network (on the layout) or at virtual tracks in the unmodelled space. With this approach, only the loaded segment of a cars journey is defined, regardless of if it is heading in to or out of the modelled layout. As part of each car’s assignment, there is always at least one segment that is done empty, either to supply a car to a shipper, or to return a car back home. With the Shipment having only information for the loaded segment, the other segments must be generated in some way. This has led to some unfortunate side effects in terms of being able to shape car movements in desirable ways.

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Still Too Much Congestion

While running simulations of the revised operating scheme whereby we have no dedicated switcher at Grand Forks, but simply let the way freights switch the industries and exchange cars between the railroads, once again there is a pile up of cars that get “stuck” in the yard at Grand Forks. This is fundamentally no different than when we had the dedicated switcher, just to a different degree. It occurs on fewer tracks, and involves less cars, but it is still an undesirable outcome that will lead to unsatisfactory operations.

One thought was that we should try to minimize the shipments that are selected during restaging to ones that have a more clear path from staging to the first delivery point. This is called “congestion” and is a measure of how full the tracks are along the car’s route to its first destination. The restaging logic now considers only those shipments where the path congestion is below a certain level, with the idea that this will help the overall car flow by not overloading the paths that already have lots of cars along them.

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What is the Best Fast Clock Multiplier?

Model railroads are often operated with a “fast clock” that runs some number of times faster than real time, in order to make travel times seem more realistic. Distances on most layouts are so short that the actual travel times between stations end up being very short. Running a clock at a faster rate increases these times to more acceptable values.

A typical fact clock ratio is somewhere around 4:1 or 6:1, as that makes a session lasting a few hours seem more like a day. But, what is the best ratio to use and why?

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Too Much Yard Switching Busy Work

The original scheme for handling cars through the Grand Forks yard was to classify all arriving cars using a local switcher, including those cars destined for the local industries at Grand Forks. A separate switching operation would then deliver them. This seemed to work well when there were only a few trains through the town each day, but with the recent additions of Carson and Curlew and their extra industries wanting more cars, this approach has broken down. More details of the first attempt at operating using that scheme can be found in the article “First Attempt at Grand Forks”. Suffice it to say that it did not go well due to the extra traffic to be handled through the Grand Forks yard. So, what to do instead? Time for some serious rethinking of the process, and a bit of detailed analysis.

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Operating Grand Forks as a Classification Yard is a Mistake

At the start of operations on the S&BC, there was very little main line track to other towns. The entire layout pretty much was the Grand Forks town, plus the upper and lower staging yards. This resulted in some traffic to and from the local industries in Grand Forks, but most of it simply was interchanged between the CPR and the S&BC and went to and from the staging yards. Consequently, it made sense to operate the yard as a classification point in order to best handle the interchange traffic.

Now, with the addition of the new towns of Carson and Curlew that have in combination more industry spots than the entire layout had before, continuing to operate Grand Forks as a classification yard is proving to be a big mistake.

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Selective Compression of Operations

The idea of selectively compressing aspects of a model railroad has been around for a long time, but has mostly been applied to physical things such as building size, number of windows, bridge length, etc. The motivation is that our model railroad layouts are significantly smaller than the prototype, so to help compensate for this, we reduce the size or number of various elements to help make the layout seem bigger. The notion that this same idea can be applied to the operational aspects of running a model railroad has not been popular, but will be explored here.

Model train sizes and distances are already vastly smaller that on the prototype, and we often operate with a “fast clock” to enhance the notion of time and distance, but there are a few more things that can be done from a timing perspective to enhance layout operations.

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