Monday, October 22, 2007

Track Plan Analysis, Part 3

For this installment, we'll assume that the model railroad track plan we are analyzing has made it over all the forgoing hurdles. With a lot of the mechanics covered, I start looking at how well the plan will work for its intended purposes.

7) Yard work never ends -- and that's a good thing

First and foremost, not every layout needs a traditional yard. Yards happen to be one of my favorite operational elements, so they're usually a high priority for me personally. But I've seen and designed some neat layouts without a textbook multi-track yard. A siding can serve the same purpose, allowing the crew to sort cars as needed for deliveries. For some small shortlines, a couple of interchange tracks with another railroad are the only yard available. And for a relatively small number of cars, destinations, and daily trains, that can work very well.

But most model railroaders want more action on their layouts than would be typical on prototype railroads. And yards are just plain neat, so most layouts include one or more. In analyzing these yard configurations, I start with a basic question. As I explained in my article in the recent Model Railroader magazine special issue, How to Build Realistic Layouts: Freight Yards, choosing the type of yard to model can make a big difference.

As seen in the image above, there are a wide variety of yard types found on the prototype, yet model railroader often are focused on "Division Point" yards. But real division points are often huge and another yard type might provide all for the same train make-up and break-down tasks that modelers desire. [I wrote a bit about the sometimes deadly urge for division point yards as one of my Eight Tricky Traps of Layout Design a few months ago.]

So I try to understand what type of yard has been intended in the layout under the analysis microscope. From that determination, I have an idea of what elements should be included and if the scope and scale of the yard is appropriate to its role on the layout.

A few basic things I look at are number, length, and the connections of yard tracks. A plethora of three-car-long body tracks may prove to be less useful than fewer, longer tracks, for example. While single-ended tracks are more space efficient for a yard, at least a few through tracks are also helpful. If a few of the classification tracks can connect directly to the main, this will be very helpful in actual operation. I also give a close look to any S-curves created in negotiating the yard ladder. And of course, my earlier check on rendering reality has already told me if the ladders are drawn too steeply or the ladder turnouts too close to one another.

Much of this analysis is naturally related to the type of yard being modeled and thus its purpose and role in the overall layout. Some elements that would be fatal in a through division point yard are completely benign in a branchline terminal, for example.

Next I will consider the mechanics of the overall yard design. Friend Craig Bisgeier's "Ten Commandments of Yard Design" is a very helpful introduction to these ideas. This useful checklist takes some unnecessary flack, in my humble opinion. Yes, it's true that not every prototype yard has a dedicated yard lead, for example. But these tended to be small yards with much lower train density than most modelers want to run. In typical model environments, a yard lead is usually a big help to keeping things flowing smoothly. All in all, I believe that most neophyte model railroad layout designers would have much better results by following Craig's advice than by ignoring it. [Maybe if Craig had called them "Tips" instead of Commandments, self-proclaimed experts wouldn’t feel so compelled to nit-pick ... but I digress.]

In particular, I'm looking for the steps that are necessary for a train to arrive, swap blocks of cars, terminate, or originate (depending on the role of the yard). How many steps are required? How many different backing moves? How often will the flow of through traffic be blocked during the process? This simple process of walking through these operations often flunks a yard that might otherwise appear to be well-designed at first glance. Sometimes the fix is simply adding or moving a crossover. Other times, it's a much more invasive procedure -- and the patient does not always survive. Many newbie model railroad layout designers lack any experience with actually operating yards, of course, so they're not able to walk through these steps, to the detriment of their designs.

My next yard test is related, and that is to try to get a sense of capacities and flows through the yard. Will the yard operators be able to keep up (if dedicated) and/or can the through train crews do their work efficiently? If not, the yard is going to be a chokepoint for operations. In both the Model Railroader special issue I referenced earlier and here on-line, I've highlighted a number of tips that can help keep yards flowing smoothly. Some are design related, some operations-related. But when I analyze a track plan, I'm trying to understand the impact of the yard configuration on the generation and flow of traffic and if there are any subtle roadblocks to efficient operation.

My final yard check is the basic appearance and "railroadiness" of the yard configuration. Compound yard ladders are very space efficient, for example, but tend to be rare on the prototype where crewmembers would need to cross tracks repeatedly to throw switches. Sometimes these complex yard ladders are the only way to make a yard fit, but I think it can detract from the overall appearance. This is pretty subjective, but I think most people have seen enough photos of real-life yards to have a sense of this.

Whew! That was a lot on yards and I'm afraid I've only scratched the surface. Again, this took much longer to write about than to actually analyze a plan. We'll talk about Cornerstones and PICS next time.
Index to all five trackplan analysis posts

I love slide guitar in all its forms: bottleneck, pedal steel, lap steel, dobro, etc. I'm slightly embarrassed to admit that it took me the longest time as a kid to figure out how players were making those sounds come out of a guitar (in my defense, it was pre-MTV). I was listening again this weekend to a fabulous collaboration album, The Word. Blues artists the North Mississippi All Stars teamed with absolute newcomer (at the time) Robert Randolph on pedal steel and producer / jazz keyboardist John Medeski (of Medeski, Martin, and Wood) for this powerful album of gospel tunes inspired by the "sacred steel" guitar tradition of some black churches. The playing is exuberant and exhilarating. Since this album, Randolph has become established as a commercial artist, releasing some other music I enjoy. But in my opinion, none matches the pure joy of The Word.