How far apart should signals be on a model railway?

In real life, UK colour light signals are 1200-1800m apart. At OO gauge this is 15-24 metres, which is far too long for most layouts. Most modellers use compressed spacing — about 600-1000mm in OO gauge — which gives a realistic impression without needing a football pitch.

Should I use semaphore or colour light signals?

Choose based on your era. Semaphore signals suit steam-era layouts (pre-1960s). Colour lights suit modern image layouts. Some transition-era layouts (1960s) use both. Check prototype photographs for your chosen location and period.

What height should signals be?

UK semaphore signals stand about 8m tall (105mm in OO). Colour light signals are about 5.5m (72mm in OO). Ground signals are about 1m (13mm in OO). Commercial signal kits from Dapol, Ratio, and Berko are made to correct scale heights.

Where should I position signals on my layout?

Place home signals before points (on the approach side). Place starter signals at the departure end of platforms. Distant signals go 400m before the home signal on semaphore lines. On model railways, compress these distances proportionally.

ModelCalcs

Signal Spacing Calculator — Realistic Placement

Work out realistic signal placement distances for your scale and era.

Gauge

Signal Type

Era

Track Length (mm)

How We Calculate This

Calculates signal spacing and dimensions based on UK signalling practice, scaled to your gauge.

UK Signal Standards

Colour light spacing: 1200-1500m real / Scale ratio
Semaphore spacing: 800-1000m real / Scale ratio
Signal height: 5.5-8m real / Scale ratio
Signal count = Track length / Spacing + 1

Frequently Asked Questions

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Last updated: February 2026

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