A track plan from the track you already own

Benjamin | TrackDrawer.com · published 15 November 2026

A track plan from the track you already own starts with counting, not drawing. What matters is the curves, not the straights: every closed loop needs 360 degrees in total, and every turnout needs its partner pieces. That turns a starter set with twelve curves into an oval, and with two small extension sets into a station with a passing loop and a siding.

How to sort and clean old track and work out which system it is, is covered in Give your old box of track a second life. This article is about the next step: what can you actually build with what is on the table?

Count first, plan second

Sort the track by type and count per catalogue number. Four groups work best:

• curves, split by radius and angle;
• straights, split by length;
• turnouts and crossings, split into left and right;
• special pieces such as feeder track, switch track, buffer stops or transition track.

The catalogue number is often printed underneath. If it is missing, a ruler helps: radius, angle and length together almost always identify the piece.

Curves are the scarce resource. Straights can go almost anywhere, but without enough curves no loop closes. That is why the next step pays off.

The angle sum: enough for a circle?

Every closed loop turns through 360 degrees once. With a system of 30 degree curves that is twelve curves, with 15 degree curves twenty-four. For a simple oval both half circles must use curves of the same radius, otherwise the two ends do not line up.

So work it out per radius: number of curves times angle. If you have, say, ten R1 curves and six R2 curves of 30 degrees each, neither radius is enough for a loop of its own. Mixing radii in one loop only works with extra filler pieces and is fiddly. A program does that sum faster than you can.

A word on straights: both sides of an oval need the same amount of straight track. An odd number therefore often ends up in a siding or stays in the box.

A worked example with C track: twelve R2 curves of 30 degrees give exactly 360 degrees. Four 24188 straights and four 24172 straights add up to 1440 mm, so 720 mm on each side of the oval. Outside the roadbed the oval then measures 2 x 437.5 + 720 + 40 = 1635 mm long and 2 x 437.5 + 40 = 915 mm deep. With a 5 cm margin all round you need a baseboard of just over 174 x 102 cm. Do this sum once by hand to see where the dimensions come from; for anything more it is too slow.

Turnouts need partners

A turnout on its own does not make a passing loop. On Märklin C track the standard turnout 24611 or 24612 needs a counter curve 24224 so that the diverging track runs on in parallel, and usually a 24172 straight to bring the through track back onto the grid. That gives a simple rule of thumb for your box:

• siding: one turnout, one counter curve, a buffer stop and some straight track;
• passing loop: two turnouts, two counter curves and enough straight in between for a train;
• station with a siding: both together, so three turnouts.

So always count your turnouts together with their partners. Three turnouts without counter curves are worth less to the plan than one turnout with one.

Example: a starter set and two extensions

How much comes out of a little shows in a measurement with the TrackDrawer Auto-designer. The starting point is the "Oval" starter set for C track in the TrackDrawer catalogue: twelve R2 curves (24230), four 24188 straights, four 24172 straights and a 24088 feeder track. On top come the extension sets C1 (24900) and C2 (24902). The baseboard is 200 x 120 cm, with a 5 cm margin.

Three things stand out. First, the curves set the shape: every plan stays on twelve R2 curves, because neither set adds curves. Second, C1, with one turnout, one counter curve and a buffer stop, makes exactly one siding possible, and C2, with two turnouts and two counter curves, exactly one passing loop. Third, something is always left over: feeder track 24088 is as long as 24188 and replaces one of the straights when you build, and extra straights do not always fit the oval symmetrically.

All four plans have fewer than 60 pieces, so they fit in a free plan.

What is missing, and what is worth buying

If you want more than your box allows, turn the question round: which plan do you like, and what do you lack for it? If you keep drawing in TrackDrawer or pick a bigger plan, the parts list shows per catalogue number how many pieces you have and how many are missing. In the Railfolio every public plan has "Make it with my track"; the Auto-designer then makes a variant from your stock and to your baseboard size.

When buying more, the same rule applies as when counting: curves and turnout partners first. A second set of curves on a larger radius opens up double track, and a counter curve turns a lone turnout into a usable siding. Ten more straights only make an oval longer.

Several systems in one box

If M, K and C track are mixed in the box, count each system separately. The geometry differs, and transitions need pieces of their own, such as transition track 24922 from C to K track or 24951 from C to M track. Plan with one main system and use the other for a clearly separate part, such as a storage yard.

Frequently asked questions

Do I really have to enter every piece?

For a plan that fits, yes. In TrackDrawer you add a starter set or extension set in one go, a long list loads as a CSV file, and with Pro a photo counts the track for you.

What do I do with single curves that are left over?

Single curves put a bend into a siding or a branch, for example towards a storage track along the edge of the baseboard. If there are not enough for a loop, plan them as an addition to the main line.

Does the Auto-designer only plan with my stock?

Yes. It only lays out variants from pieces in your stock, and never more than you have. How it works is explained in The Auto-designer: layouts from your own track.

Try your own box

Enter your stock, choose your baseboard size and let the Auto-designer show what your track adds up to.