How far apart should points be?

Leave at least one vehicle length of straight track between consecutive points so a long coach or bogie wagon is never spanning two sets of moving switch blades at once. For OO gauge with standard 260-280mm coaches, allow at least 280mm of straight between the frog (V-crossing) of one point and the toe (switch end) of the next. Shorter sidings and yard pointwork can be tighter because speeds are low.

What size points should I use?

For mainline running use medium (Peco SL-95, 219mm, 12° frog) or large radius (SL-88, 259mm, 12°) points so long coaches and bogie stock track smoothly. Small radius (SL-91, 185mm, 12°) points are best kept for sidings and yards where speed is low. Peco Streamline offers small, medium and large radius turnouts in OO; N gauge code 80 has a medium (SL-395, 123.7mm, 12°) and large (SL-388, 160mm, 8°) plus the tighter Setrack ST-5 (87mm, 22.5°).

What is the correct track spacing for parallel tracks?

Peco Streamline standard OO double-track spacing is 50mm centre-to-centre — generous radii allow down to about 44mm (the 4mm-scale prototype minimum) before adjacent coaches foul on curves. Hornby Setrack uses a wider 67mm fixed geometry. N gauge runs at roughly 25-26mm centres. Tighten spacing only on straight track and check clearances with your longest stock on the sharpest curve before committing.

How do I plan a crossover?

A crossover connects two parallel tracks using two points facing opposite directions. The along-track footprint it occupies equals the track-centre spacing divided by tan(frog angle): at the Peco 12° frog, a 50mm-centre OO crossover needs about 235mm of bench length. Use matching point sizes for both sides, and keep the straight section between the two frogs long enough for your longest vehicle.

ModelCalcs

Point Spacing Calculator — Turnout Layout

Work out correct spacing between turnouts and crossings for smooth operation.

GaugePeco track range for your scale

Point SizeLarger radius = smoother for long stock

Track Spacing (mm)

Centre to centre, parallel tracks (Peco OO standard 50mm)

Longest Vehicle (mm)

Over-buffers length of your longest coach or wagon

How We Calculate This

Calculates turnout spacing using verified Peco point dimensions (length and frog angle) and track geometry. Pick your gauge and point size and the calculator pulls the real Peco part length and frog angle, then works out the straight you need between points and the bench length a crossover occupies.

Formula

Min straight between = Max(Longest vehicle, Point length × Safety margin)
Crossover footprint = Track spacing ÷ tan(Frog angle) — the along-track bench length
Clearance length = Longest vehicle + 50mm

All Peco OO Streamline turnouts (small/medium/large) share a 12° frog. N gauge mixes 12° (medium) and 8° (large) frogs; the calculator uses the correct angle for each, so the crossover footprint reflects the real part you would buy.

Frequently Asked Questions

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Last updated: June 2026

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