An H0 layout on 180 x 90 cm: what fits?

Benjamin | TrackDrawer.com · published 29 October 2026

A baseboard of 180 x 90 cm takes exactly one loop in H0 and OO, on the smallest radius of your track system (around 360 mm). Inside it there is room for sidings, a small yard and, with six of the ten systems, a passing loop or a station with two platforms. A second, wider loop or double track does not fit: 90 cm is not deep enough for that.

Why depth is the limit

The 180 cm width gives you running length; the 90 cm depth decides which curves you can use. A loop is as wide as twice the radius plus the width of the track:

• Märklin C track R1: 2 x 360 mm + 40 mm roadbed = 760 mm.
• On 900 mm of depth that leaves 140 mm: a 50 mm margin on each side to the edge, plus 20 mm to spare per side.
• The next radius, R2 at 437.5 mm, is already 2 x 437.5 + 40 = 915 mm wide. It does not fit even without a margin.

The other systems tell the same story. Hornby R1 (371 mm, 29 mm wide) comes to 771 mm, Kato R370 with its 41 mm roadbed to 781 mm. Everything fits on the smallest radius, and that is where it ends.

What the Auto-designer lays on it

TrackDrawer had the Auto-designer design on 180 x 90 cm with a 50 mm edge margin for each track system, from a typical box of track: per radius a full circle plus four curves, eight each of the first six straight lengths, three left and three right turnouts, four counter curves, four compensation pieces, one crossing and three buffer stops where the system has them. It searched with the goal continuous run, and with the goals several trains and station together.

What the table tells you:

• A plain oval works everywhere. With C track that is 22 pieces and 4.11 m of track, with Roco Line 14 pieces and 4.09 m.
• Sidings are the easiest addition. For eight of the ten systems the Auto-designer lays three sidings, or a siding with a yard, inside the loop. That adds roughly 1.5 to 2.5 m of track for shunting.
• A passing loop is tight. Two turnouts with counter curves and compensation pieces need a long straight side. With Märklin C, M and K, Roco geoLine, Fleischmann Profi and Hornby it works on 180 cm. Piko A needs 185 cm, Kato Unitrack H0 190 cm and Roco Line 200 cm, because their turnout with counter curve and compensation is longer: 470 to 575 mm per end, against 325 to 400 mm for the others.
• Tillig Elite stays with an oval. Tillig has no counter curve in the catalogue; then the Auto-designer only lays turnouts as a crossover between two loops, and the baseboard is too shallow for two loops.
• Märklin K also fits on the standard radius. The longest variant is a station with two platforms on the 360 mm standard radius, not on the tight 295.4 mm industrial radius. A loop with a passing loop on the industrial radius already fits on 140 x 75 cm.

Two shapes in the list need explaining. The "triangle on R1" of 12 pieces and 2.26 m is really a circle: there is no room for straight sides. And a "diamond" is a skewed loop with corners of 60° and 120°, which on this baseboard can give as much track as an oval. More about the shapes in the Auto-designer; the space per radius for C track is in how much space for Märklin C track.

A 360 mm radius and long coaches

The smallest radius is exactly what makes 180 x 90 cm possible, but it comes at a price. The longer a vehicle, the more it overhangs the track in a curve: the middle swings inwards, the ends outwards.

A worked example for a coach 300 mm long with bogie centres 220 mm apart:

On 360 mm that is noticeable. Three consequences:

• Side by side. If two tracks run close together in a curve, the overhanging corners can touch. How far apart tracks need to be is covered in track spacing.
• Couplings and buffers. Between two long coaches, the couplings shift a lot relative to each other in a curve. In an S-bend with no straight in between, buffers can lock. TrackDrawer gives a tip when two opposite curves have less straight between them than a standard wagon is long; for H0 the app uses 250 mm.
• Looks. A long passenger train on R1 looks cramped, even when it runs well. Shorter coaches, goods wagons and four-wheel coaches suit a small layout better.

Which radius your rolling stock can handle is stated by the maker of that stock. In TrackDrawer you can add your rolling stock to the plan; the check then warns at every tighter curve. If you set a minimum radius in the Auto-designer above the smallest curve, it will find no loop on 90 cm depth: R2 in C track needs 1015 mm with a 50 mm margin, so a baseboard 105 cm deep.

H0 or OO

OO is the British scale of 1:76 on the same 16.5 mm track as H0 (1:87). The trains are bigger on the same rails. Hornby R1 (371 mm) fits on 90 cm with 64.5 mm per side, but the vehicles overhang more than H0 models of the same prototype; TrackDrawer uses a standard wagon of 285 mm for OO.

Frequently asked questions

Does double track fit on 180 x 90 cm?

No, not as two full loops. The second loop has to be on a larger radius, and for every system that is wider than 90 cm. If you want two trains running, look to a passing loop (six of the ten systems manage one at this size) or choose a deeper baseboard.

Is 180 x 90 cm enough for a first layout?

Yes, for a loop with sidings and some shunting. If you want a station with a passing loop with Piko A, Kato Unitrack H0 or Roco Line, allow a little more width: 185, 190 or 200 cm.

Try it yourself

Look at the C track plans in the Railfolio, or enter your own track and let the Auto-designer show what fits on your 180 x 90 cm.