How fast should an OO gauge train run?

A real express train at 125 mph (201 km/h) at OO gauge (1:76) should travel at about 2.64 km/h or 734 mm/s on the layout. That is roughly 73cm per second — surprisingly fast for a model. Most modellers run their trains somewhat slower than true scale speed for visual appeal.

Does scale speed apply to RC cars?

Yes, though RC cars are typically designed for exciting performance rather than scale realism. A 1:10 RC car doing 50 km/h is equivalent to 500 km/h at full size, which is beyond any real road car. Scale speed calculations help you set realistic speed limits for scale events.

Why does speed scale linearly, not cubically?

Speed is distance per unit time. Since distance scales linearly with the scale factor (1:72 means 1/72nd the distance), and time is not scaled, speed also scales linearly. Weight scales cubically because it depends on volume (three dimensions), but speed is only one-dimensional.

ModelCalcs

Scale Speed Calculator — Realistic Model Speed

Calculate how fast your model should move to match a real-world speed at scale. Essential for model railways and RC models.

Real-World Speed

Speed or rate value

Speed Unit

Select your preferred measurement unit

Scale

Select the model scale

How We Calculate This

Speed scales linearly — divide the real speed by the scale factor.

Formula

Scale speed = Real speed ÷ Scale factor

Example: A real train at 100 km/h on an OO gauge (1:76) layout:
100 ÷ 76 = 1.316 km/h = 365.5 mm/s on the model.

The result in mm/s is most practical for model railways, as it gives you the actual distance the model should travel per second on the layout.

Frequently Asked Questions

Related Calculators

Scale Calculator

Convert any measurement between real world and model scale. Supports all common scales.

Real to Scale Converter

Convert a real-world measurement down to your chosen model scale.

Scale to Real Converter

Convert a model measurement back up to find the real-world equivalent.

Scale Ratio Calculator

Find the scale ratio from a real measurement and its model equivalent.

Mixed Scale Calculator

Convert a measurement from one model scale to another without going back to real size.

Last updated: February 2026

All calculations are estimates. Always verify quantities before purchasing materials.