TY'S MODEL RAILROAD: Track

Benchwork

One Year Anniversary

By Ty’s Model Railroad - 4/03/2011 04:15:00 PM

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Track

Track Adjustments

By Ty’s Model Railroad - 3/27/2011 06:49:00 PM

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Track

Fixing the Grade

By Ty’s Model Railroad - 1/24/2011 08:08:00 PM

Before and after of a track grade from 10% to 6%

As this is my first layout, almost every aspect of the construction of model railroading is new to me. Most tasks are trial and error and the amount I’m learning is extraordinary. At the same time, I’m also seeing where I went wrong, and the biggest error so far is the grade leading off my trestle down to the 60 degree crossing. This has been a huge issue since I first designed the layout. Engines would get high centered at the top of the hill and the engine's cattle guards would catch on the grade crossings, always causing a derailment. This grade had to go, so back to the drawing board I went. With a little better planning, I managed to take the grade from almost 11%, down to just over 6%.

Before photo of an original section of benchwork leading up to a wooden train trestle

I removed the entire grade to start fresh. I took two things into account when redesigning the grade. The first was that I needed to try to make the distance from the 60 degree crossing to the end of the trestle longer. Second, I had to decrease the height of the trestle. These two items were essential in making a more successful grade.

After photo of a section of benchwork that was cut back in length

To do this, I removed about 4 1/2" of the track structure leading up to the trestle, thus allowing me to move the trestle further over to the right of my layout. Second, I had to lower one end of the trestle. The trestle had almost 3/4" clearance above passing trains, so with a few modifications I lowered the trestle about 1/2” on one end. The trestle now has a down grade of about 2%.

Foam risers from Woodland Scenics replacing custom foam risers leading down from wood train trestle

For the rest of the grade, I used a 4% foam starter grade from Woodland Scenics. This allowed me to easily transition from the crossing level up to the edge of the trestle. I then used custom cut foam shims to support the new grade and to make it as smooth as possible. I added foam roadbed and one continuous piece of flex track to ensure a continuously smooth track. The end result was flawless. No more derailments and no more high centered engines!

A reduced track grade leading down from a wooden train trestle

Calculating and Working With Grades

Most prototypical modelers will tell you to build nothing with a grade over 2%. For small layouts such as mine, this isn't always possible. This is especially true if you want a layout with lots of visual interests such as tunnels, bridges, mountains and curves. To calculate grade, use the following formula:

(rise / run) x 100 = slope %

For example, say your track needs to go from point A at 0.5" elevation to point B at 4.5" elevation, a height difference (rise) of 4", and you have a 200" distance (run) between point A and B. Take the rise and divide it by the run (4 / 200). Now take that number and multiply it by 100 to get your grade percentage, which is 2% for this example.

As you can see, you would need at least 200" (16.6 feet) to raise your track 4" in elevation at a maximum grade of 2%! Unless you have a massive layout, this just isn't possible without going above 2%. Most often, you should be able to get away with grades up to 6% without many issues, though these are no longer prototypical. Keep these points in mind when planning your layout and grades:

Plan first and know your limits. When designing your layout, try to give yourself as much room as possible. The more room you have to get from point A to point B, the lower the grade will be and the less headaches you will have. There are physical limits to how steep your train can travel, especially with rolling stock.
Keep your grade as consistent as possible with smooth, gradual transitions at each end. This is almost more important than the grade itself. Transitions into and out of your grade that are too immediate will create sharp humps and valleys, resulting in engines getting high centered at the top and bottoming out at the bottom. The longer the locomotive, the more of an issue this will be. Sharp transitions can also cause rolling stock to uncouple.
Grade crossings require level track leading up to them to prevent couplers and cattle guards from catching on them. If you have a road grade crossing on your track grade, make sure the grade is no more than 2% for at least 8” before the crossing.
Experiment and test often as you build. Play around with different grades with actual track and engines before you make anything permanent. Allow for adjustments, and if it doesn’t work the first time, find what’s causing the issue and retry.
Don’t let anyone ruin your fun. The 2% rule is the standard for prototypical models that mimic real life track grades, and even in real life there are exception to that rule. The Pennsylvania Railroad operated by Madison Railroad has a grade of 5.89%! Make a layout as you see fit, after all it’s your train and your imagination. Do what makes you happy and proud.

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Track

Turnouts & Switch Machines

By Ty’s Model Railroad - 9/15/2010 09:58:00 PM

I have now installed four new Atlas under-table switch machines, one Atlas trackside switch machine, and a new motor for my Atlas turn table. I have also been collecting the various parts and components for the control panel that I am designing. I still need four Atlas snap-relays as well as the dual cab MRC controller I’ve had my eye on. I will have more details on this when I get a more finalized plan on its design.

The under-table switch machines installed pretty easily, with only a few adjustments needed. The hardest part was keeping them positioned while screwing them in. A partner definitely helps with this step. One issue that did need some attention was the ease of movement of the turnout itself. The switch machine motors themselves are pretty powerful, especially with a 16V AC burst of power. However, the issue comes from the very small distance of the switch machine's movement as well as the slight flexibility of the plastic pin that attaches to the track switch point.

Atlas under table switch machines with wiring installed below wooden benchwork

The switch machine's movement is just barely longer than the distance of the turnout point itself. This means that there is very little room for error when installing the switch machine as it needs to be installed perfectly centered with the turnout. Also, because the small pin that moves the switch point has a bit of flex, ANY resistance in the track switch point will prevent it from fully engaging. Because of this, I ended up having to remove the roadbed under the sliding bar of the turnout to ensure there was no resistance. After a few adjustments, the track turnout moved much more easily and everything worked fine.

As for the wiring, each switch machine will be on an independent Atlas switch controller; green wire being for the main line and yellow being for the turnout. All are grounded by a common wire which is the center brown wire. Switches 2 and 3, which branches from the main line to the front spur, are on a common switch and operate in unison as they will always need to be switched together when crossing off of or onto the main line.

Atlas trackside switch machine installed beside an Atlas turnout on a model railroad layout

Unfortunately, I was not able to install an under-table switch machine to the turnout to my turn table. Because of this, I had to use a trackside switch machine. I wired it just as I did with the under table switch machines and attached it to the same brown common lead. I will have to find some way to hide this machine in the future. I have also attached my new turn table motor. It works great, but is a little loud. Hopefully this will be quieted slightly when the cover is attached. With that, there is where I am this rainy Wednesday evening.