Understanding a Model Railroad Prototype

Understanding a Model Railroad Prototype

Find Part 1: Introduction here: http://www.trainsanddioramas.com/planning-a-model-railroad-sacramento-southern-in-n-scale-introduction/

Arriving at layout dimensions

Here we are not talking about the history anymore, and we’ll dive straight into the technical details of the design. First question is: ‘What am I modeling and how much space will it take?’ The Central Pacific Freight Depot is the starting point of the journey. First I found the place in Google Maps (as you can see in Figure 1), it is on the right of the Delta King Hotel, at the junction of the Front St and K St. Note that Google Maps works very well (specially in satellite view), but Google Earth gives certain additional features like flexibility in navigation, 3D rendition and most importantly measurements that help in the design process. I generally use Google Earth, and for the remainder of this design that’s what I will use, but one can follow the same steps in Google Maps too.

Figure-1: Google Map view of Old Sacramento Historic District.

Now Google always presents the maps in normal orientation, i.e. North on top and East on right which is very helpful for regular use, but in this case, it is a little difficult to visualize the area as a layout in that orientation. Other than island layouts, most model train layout designs are stuck against a wall and designed on shelves of various kinds. Now it is helpful from a design standpoint if I can orient the map the way it would look on a shelf. Given my focus is only on the railroad bit, I’d put East on top, and North on the left. I have also zoomed in to restrict the area between I St. bridge and the Tower Bridge, keeping the Sacramento river in front of me. Obviously, the riverfront structures would be a great attraction for the layout so I have decided that the observer is looking at the model from the river side. Figure 2A shows my primary area of attraction in 3D view, if you look at this section it already resembles a proper shelf layout. Figure 2B, the zoomed in view focuses just on the railroad facilities – the track, the depot, the turntable and the erstwhile roundhouse that is now the part of the CSRM exhibit, and a little bit of waterfront detail opposite the depot before all tracks merge into a single line running towards Baths.

Figure 2A: Sacramento Southern Railroad along with Sacramento River – Shown here is the section between the I St. Bridge and the Tower Bridge.
Figure-2B: A selected section of Figure 2A focusing primarily on the track and railroad buildings.

Both Figure 2A and 2B can be very effective shelf layouts – 2A for a larger area of course that includes the beautiful waterfront scene, and 2B for a smaller area but keeping all the railroad structures intact but eliminating much of the waterfront details (including the steamer that is now the Delta King Hotel). I intend to keep the I St. bridge entrance on the left of the frame in the design in a way that the cross-section of the bridge ends at the edge of the layout. This provides a nice way to hide the exit of the track from the scene. The I St. bridge in itself is a fantastic railroad attraction. Built in 1911 this twin-deck swing bridge has Union Pacific track on the lower level and a road access on the upper. With creativity this bridge can also be incorporated in a layout, but we’ll not talk about that in this article. Now, for the purpose of this article, I will try to fit the area in Figure 2A into a layout and see how that goes. The same methods can be applied to the area in Figure 2B for a smaller layout footprint.

Let’s start with the next important thing – measuring the prototype. Since my area of interest is the whole area between the I St. bridge and the Tower Bridge (in length) and from Front Street to the port side of the old steamer that is now a Delta King Hotel, I would use the Google Earth measurement tool to measure my footprint. For this, first I go back to the top/2D view and click on the ‘Show Ruler’ button in the view as shown in Figure 3.

Figure-3: Ruler in Google Earth is an essential tool to measure dimensions of various prototype objects.

A new pop up opens up as shown in Figure 4 and you see a square cursor on the screen. I used the cursor to take my first measurement – from I St. bridge to the Tower Bridge along the edge of the river. Notice that dimensions are in inches in the display – you can change that using the drop down beside the dimension to any type of unit you want. I have measured each dimension in inches because that will be used for scale conversion, and in meters to give an idea of distance between the two points in 1:1 scale.

Figure-4: Before saving a ruler the user can select the unit of measurement.

Once you hit ‘Save’ in the Ruler call-out in Google Earth as shown in Figure 4, it will show another call-out window as shown in Figure 5 where you can provide more details about the measurement that you’ve just taken. In the name section I put what I am measuring so that I don’t have to open the description every time to know what it is, and I use a different style/color for each measurement in the second tab for easy identification. Once you hit OK, the ruler is saved as shown in Figure 6 – in this case I used the red line.

Figure-5: While saving a ruler, a user can add a lot of details for easy identification as well as additional information pertaining to the measurement taken.
Figure-6: A saved ruler showing the distance between I St. Bridge and the Tower Bridge.

In Figure 7, you can see all the major dimensions I have taken for both the layout approaches – the big one with all-inclusive scenery as shown in Figure 2A, and the smaller one focusing on the railroading bit that you see in Figure 2B. Dimensions are provided with two units as mentioned before – inches and meters (rounded off to the nearest whole number). You can measure these dimensions directly in Google Earth and save the image from Google Earth itself without using another software for screen capture (though those dimensions won’t be shown automatically unless you use it in the name section of the dimensions – a trick I will show for more minute measurements later). Figure 8 shows how to save an image directly from Google Earth.

Figure-7: Major dimensions for layout approaches in Figure 2A and 2B. Dimensions are mentioned in inches and meters against the ruler and just in inches in the legend.
Figure-8: Saving an image with a ruler can be helpful for future reference.

So, what is the big reveal after the first measurement exercise? Benchwork dimensions – and this is why we used inches (one can use centimeter or meter also based on the level of comfort with those measuring units). The below table shows the conversion:

So, what is the big reveal after the first measurement exercise? Benchwork dimensions – and this is why we used inches (one can use centimeter or meter also based on the level of comfort with those measuring units). The below table shows the conversion:

Layout InspirationRuler Color Code in Figure 7DescriptionMeasurement (inches)N scale measurement (inches)N Scale Measurement (feet)
Figure 2ARedDistance b/w I St. bridge and Tower Bridge, approach roads included2688026880/160=168168/12=14
Figure 2AGreenDistance b/w the river and end of the Roundhouse38163816/160=23.85 ~ 2424/12=2
Figure 2ABlueDistance b/w Front Street Parking and port side of Delta King Hotel steamer37603760/160=23.5~2424/12=2
Figure 2BOrangeDistance b/w I St. bridge and south end of the Café Complex1824018240/160=114114/12=9.5
Figure 2BPurpleDistance b/w the bike trail and the roundhouse wall20802080/160=131 ft 1 inch
Figure 2BYellowDistance b/w the Delta King Hotel entrance and Front St. parking22402240/160=141 ft 2 inches
Table showing conversion of key measurements to arrive at scale dimensions of the layout

Our final layout dimension stands at:

Layout for Figure 2A – 14 ft X 2ft in N scale

Layout for Figure 2B – 9.5 ft X 14 inches in N scale

Both the dimensions are pretty manageable for most household. I will focus on the bigger layout from here on and will see how it takes shape. Now, before we proceed to the next step, one final thing to decide on: Traffic movement. In the prototype, the traffic movement is basically point to point – from Depot to the Baths and return. So, for my design I am happy with a staging yard ‘off stage’ beyond the Tower Bridge crossing to represent Baths. However, if space allows, it is possible to make another module/section in place of the staging that shows Baths – an option that I will evaluate later.

More measurements

Effective design means a lot of details. Before we can dive into the track planning, there are a few more things that we need from Google Earth or Google Maps – dimensions of the key buildings and landscape features and help in detail 3D visualization of the prototype. So now that we understand how measurements are taken, let’s identify the individual items and start taking measurements. At this point I am only interested in the footprint of individual buildings and features. While building these models (most of which will have to be scratch-built), more detailed dimensions will be required, and the same technique can be applied there.

In order to show the details, I have broken down the area in two parts – I St. bridge to the Central Pacific Passenger Station, and then Central Pacific Freight Depot to the Tower Bridge crossing. Figure 9 shows the dimensions of the first section – notice that I have also taken dimensions of the turnout distances, which will be immensely helpful during the track planning process. The dimensions are identified using color coded rulers on the map, where the ruler descriptions are shown in the sidebar of the navigation pane. I have put the descriptions in a way that the descriptions of the color-coded rulers in the pane identify the items that are being measured and also show the dimensions in inches (as shown earlier, this can be changed to any other unit depending on user’s preference). Also note that ‘L’ denotes length, and ‘D’ denotes Depth throughout the process.

Figure-9: Detailed dimensions of various land based items between I St. Bridge and the end of the CP Passenger Station.

An important thing to note in Figure 9 is that all the Layers are turned off and the view is basically 2D and not 3D. This is immensely helpful for taking minute dimensions since 3D rendering often provide inaccurate dimensions. Also, what is interesting is that the 2D image is from a different time, possibly much older and shows a very different landscape than the 3D image of the same area as we saw in the previous images. It also shows the tracks much more clearly than the 3D rendered image making it easier for me to take proper dimensions this time.

Figure 10A shows the other part of the stretch from the Depot to the Tower Bridge crossing. Notice that due to the waterfront structures and the docks, the dimensions are much more crowded and complex. Hence, I have provided the individual dimensions in a separate image, Figure 10B. That’s a lot! But those really are just the basic dimensions of all major structures that are bare minimum for the planning process.

Figure-10A: Various color-coded rulers measuring a variety of objects between CP Freight Depot and the Tower Bridge.
Figure-10B: Dimensions of the rulers in Figure-10A.

In fact, even for planning, I will have to delve deeper to the next level of details as shown in Figure 11 and will have to do this for the entire stretch. Figure 12A shows the detailed dimensions of the depot and Figure 12B shows the Depot in 3D – both will be required for planning the layout, as well as while building the structure. Details dimensions and 3D visualization will be required for each of the buildings throughout the planning and building process, however, Google Earth can really become helpful here providing the opportunity to drill down to the smallest of details. For the perfectionist, sky is the limit with this tool when planning and building a prototypical model railroad.

Figure-11: Detailed dimensions of various land based items between Delta King Hotel entrance and Rio City Café.
Figure-12A: Detailed dimensions of the CP Freight Depot.
Figure-12B: 3D visualization of the CP Freight Depot in Google Earth – looking South.

Join me in the next installment of this layout planning deep dive where I will show you how to take all that dimensions and details and convert them into proper N Scale dimensions.

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