Scale Speed

17 04 2013

How fast should you run your trains? It’s one of those questions of personal opinion that can erupt into heated debate in some modeling circles. We’ll leave your idea of appropriate speeds up to you. There are certainly no posted speed limits on our model trains, but for those who are interested in reproducing a more accurate scale speed, this post should help.

speed

Like the extended exposure on this photo, a model trains scale, our proximity to it, and other factors can create different impressions of speed.

Before you can determine what the appropriate speed is for model trains to be realistic, you need to think about what speeds are realistic for the prototype. And the truth is, that number can be anywhere from 1 to 150 miles per hour.

When switching for example, when switching cars in a yard, anything up to 4 mph is a coupling, 5+ mph is a collision. Geared locomotives like Shays and Heislers had a top speed of around 15 mph. Even a heavy mainline train on a steep grade might struggle to keep its speed above 20. Yet that same train could be rolling at nearly 70 on the level.

Acela

For a train like the Acela, full-throttle may not even be fast enough!

For passenger trains, speeds might be as slow as 30 or less on branch lines. Meanwhile, the Limited’s and streamliners might cruise at better than 100 down the mainline.

What’s “right” really depends on what you’re trying to model.

6-11368 Western Maryland

The Shay had a very modest top speed of about 15 mph. But with those three pistons and low gearing, they sounded like they were doing about 90 at that speed.

That being said, we can determine how fast our trains are really going. The numbers on the dial of your transformer or cab can give you some indication, but these rarely equate to the actual scale speed.

Instead, we can figure out our train’s speed in much the same way train crews once did: by timing the run between a fixed set of points. Train crews once used mile posts, or even telegraph poles, to help determine their speed. We’ll apply the same principle.

7002

When 7002’s crew determined they set a record speed on 127.1 mph, they did so by timing the passing mile posts with their watches.

You can use almost anything to mark your speed zone on your railroad: telephone poles, sign posts, even just a dab of paint on a tie. All that matters is that the distance is correct and you and your other operators know where they are.

Next, simply time the train as it passes between the two points. You don’t need to be as accurate as a radar gun – these are just model trains after all – but even a general frame of reference can be helpful.

Now to make it really easy for you! Just use the tables below to determine your trains’ speed. We’ve figured this out for both O and S Scale by reducing miles / kilometers per hour into feet/meters per second. Just set your posts 3 feet or 1 meter apart. The times listed in this table are in seconds.

Print out a copy of this table (or make your own using only the data you need) and post it somewhere near the speed trap for reference. While the times are fairly precise, a good “guestimate” while you’re running should give you a pretty good perspective.

Give it a try – you might be surprised how fast, or how slow, you’re really running those trains.

MPH O S KM/H O S
15 6.55 8.73 15 11.52 15.36
20 4.91 6.55 20 8.64 11.52
25 3.93 5.24 25 6.91 9.21
30 3.27 4.36 30 5.76 7.68
35 2.81 3.74 35 4.94 6.58
40 2.45 3.27 40 4.32 5.76
45 2.18 2.91 45 3.84 5.12
50 1.96 2.62 50 3.46 4.61
55 1.79 2.38 55 3.14 4.19
60 1.64 2.18 60 2.88 3.84
65 1.51 2.01 65 2.66 3.54
70 1.4 1.87 70 2.47 3.29
75 1.31 1.75 75 2.3 3.07
80 1.23 1.64 80 2.16 2.88
85 1.16 1.54 85 2.03 2.71
90 1.09 1.45 90 1.92 2.56
95 1.03 1.38 95 1.82 2.42
100 0.98 1.31 100 1.73 2.3
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4 responses

17 04 2013
Friscosteam

Thanks for doing the chart for us… could you extend it down to 1 mph? I operate some Legacy locos as slow as possible and it might be fun to see just “how slow they go”!

19 04 2013
Joe

Could you also calculate it for HO I have both O and HO Layouts

22 04 2013
lionelllc

Joe, I calculated speed tables for other scales for a similar article for About.com. Here’s the link: http://modeltrains.about.com/od/operatingmodeltrains/a/Scale-Speed-For-Model-Trains.htm

24 04 2013
Joe

Thank You Incidentally I use a lot of the ideas from this blog on my HO layout as well. It is useful espically for those of us who are not rivet counters.

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