An H0 layout on 240 x 120 cm: what fits?
Benjamin | TrackDrawer.com · published 1 November 2026
A 240 x 120 cm baseboard takes an H0 double-track oval, or an oval on a wide curve with a station, sidings and a small yard. The Auto-designer laid 9 to 13.3 m of track per system, against 4 to 6.6 m on 180 x 90 cm. The difference is mostly the depth: 120 cm allows the second or third radius, and with it two full loops side by side.
What 30 cm of extra depth does
At 90 cm deep, H0 only fits the tightest radius. At 120 cm deep, with a 5 cm margin on both sides, you have 110 cm for the outside width of a loop. A loop is twice the radius plus the width of the track. The largest curve that fits:
| System | Track width | Largest radius that fits | Loop outside width |
|---|---|---|---|
| Märklin C track | 40 mm | R3, 515 mm | 1070 mm |
| Märklin K track | 32 mm | Normalkreis II, 424.6 mm | 881.2 mm |
| Märklin M track | 27 mm | R2, 437.4 mm | 901.8 mm |
| Roco geoLine | 38.5 mm | R4, 511.1 mm | 1060.7 mm |
| Roco Line | 30 mm | R4, 481.2 mm | 992.4 mm |
| Piko A-Gleis | 43 mm | R3, 483.75 mm | 1010.5 mm |
| Fleischmann Profi-Gleis | 25 mm | R3, 483.5 mm | 992 mm |
| Kato Unitrack H0 | 41 mm | R490, 490 mm | 1021 mm |
| Tillig Elite | 27 mm | R31, 484 mm | 995 mm |
| Hornby (OO) | 29 mm | R3, 505 mm | 1039 mm |
On K track the next curve, Großkreis I at 553.9 mm, is already 1139.8 mm across; on M track R2 is the largest radius in our catalogue. For the other systems the step to the next radius is just too much: C track R4 needs 1198.6 mm, Roco Line R5 1115.6 mm.
What the Auto-designer lays on it
We had the Auto-designer work on 240 x 120 cm with a 5 cm margin for each track system, from a typical box of track: per radius a full circle plus four curves, eight of each of the first six straight lengths, three left and three right turnouts, four matching curves, four make-up pieces, one crossing and three buffer stops where the system has them. It searched with three goals: continuous running, several trains with a station, and variety. The table shows, per system, the variant with the most track and the longest double track among the suggestions.
| System | Longest variant | Pieces | Track | Double track among the suggestions |
|---|---|---|---|---|
| Piko A-Gleis | Double track R2/R1, plus passing loop and yard | 68 | 13.34 m | same variant |
| Roco Line | Double track R3/R2, plus 2 passing loops | 54 | 12.27 m | same variant |
| Märklin C track | Double track R3/R2, plus siding and yard | 69 | 11.97 m | same variant |
| Roco geoLine | Double track R4/R3, plus siding and yard | 59 | 11.48 m | same variant |
| Märklin K track | Double track Normalkreis II/I with crossover, plus 2 sidings | 77 | 10.74 m | same variant |
| Tillig Elite | Double track R31/R21 | 76 | 10.70 m | same variant |
| Fleischmann Profi-Gleis | Double track R2/R1 with crossover, plus passing loop and siding | 59 | 10.13 m | same variant |
| Kato Unitrack H0 | Station on R370, plus 2 sidings | 65 | 9.36 m | none |
| Hornby (OO) | Oval R2 with passing loop, plus siding and yard | 49 | 9.15 m | none |
| Märklin M track | Double track R2/R1 with crossover | 64 | 9.05 m | same variant |
What the table tells you:
- Double track becomes the norm. For eight of the ten systems the longest variant is a double track with two loops side by side. Two trains can then run at the same time without waiting for each other.
- A crossover joins in. With K and M track and with Fleischmann Profi two turnouts link the inner and outer loop, so a train can change tracks. How far apart those tracks lie is explained in track spacing.
- Stations with a passing loop. With C track the designer also lays a "Station on R3, plus 2 sidings" (52 pieces, 8.80 m) and a station with two platform roads on R3 (44 pieces, 7.44 m). With Roco Line a two-platform station fits on R4, with Piko A on R2. geoLine, Profi, Kato Unitrack H0 and Hornby now get passing loops too: with geoLine a double track R4/R3 with crossover, passing loop and siding (52 pieces, 10.94 m), with Kato a station on R370 with two sidings (65 pieces, 9.36 m).
- The dogbone appears. Every system has a dogbone among the suggestions, for example with C track on R1 with a siding and yard (48 pieces, 7.30 m). Why that shape suits an oblong board is covered in the dogbone.
- A plain oval is now roomy. The oval on the largest radius takes only 18 to 40 pieces and gives about 5.6 m of track; with C track on R3 it is 32 pieces and 5.69 m.
For Kato Unitrack H0 and Hornby there was no double track among the suggestions with this box of track; there the designer gets its length from a passing loop, sidings and a yard inside a single loop.
How long can your station be?
At 240 cm wide there is a good straight between the two half circles. With C track on R3 that is 2400 mm minus 2 x 50 mm margin minus 2 x 535 mm (the radius plus half the roadbed): about 1.23 m per long side. A passing loop with turnout and matching curve costs 360 mm at each end, leaving about 0.5 m of clear platform road. Use R2 for the curves and the straight becomes 1.39 m, with about 0.67 m clear.
That is enough for a locomotive with one or two coaches, or a short goods train. For a longer train, move the turnouts partly into the curve, or choose a plan with sidings instead of a through station.
Reach
You cannot work a 120 cm deep baseboard from one side everywhere. A reach of about 60 to 70 cm is the limit for most people. So stand the board free in the room, leave an aisle at the back, or keep the rear half simple: a loop without turnouts needs little maintenance. A tunnel at the back is best made removable.
Frequently asked questions
Is 240 x 120 cm enough for double track?
Yes. For eight of the ten systems in our measurement the Auto-designer laid a double-track oval, usually on R2 and R3. The inner loop then sits at the system's track spacing next to the outer loop.
Can I use R4 or R5 on 120 cm?
With Roco geoLine and Roco Line, R4 still fits. With C track it does not: R4 is already 1198.6 mm wide across the roadbed. If you want to run C track on R4 or R5, you need about 130 to 145 cm of depth. The sizes per radius are in how much space for Märklin C track.
Try it yourself
Compare with what fits on a smaller board in an H0 layout on 180 x 90 cm, look at other people's plans in the Railfolio, or enter your own track and let the Auto-designer show what fits on your 240 x 120 cm.
