The double slip: when you need one
Benjamin | TrackDrawer.com · published 6 November 2026
A double slip is a diamond crossing on which trains can also change tracks, in both directions. It gives you four routes in the length of a single turnout. You need one where tracks cross and you also want to switch between them, above all in a station throat where you have run out of length; on a simple layout two ordinary turnouts do the same job with less fuss.
What a double slip does
An ordinary diamond crossing has two routes: each track runs straight across the other. A double slip has four. The two straight roads stay, and two curves are added that lead from one track to the other. A train coming in from the left can carry straight on or curve onto the crossing track, and so can a train from the other side. A single slip has only one of those two curves; there is none in our catalogue.
The dimensions show where the double slip comes from. In almost every system in our catalogue it has the same angle as that system's regular turnout, and often the same length. The C track double slip 24624 is 188.3 mm long and crosses at 24.3°, exactly like the 24611 turnout and the 24640 crossing. It is, in effect, a crossing with two turnouts built in.
Double slips in our catalogue
| System | Double slip | Angle | Length | Regular turnout with the same angle |
|---|---|---|---|---|
| Märklin C track | 24624 | 24.3° | 188.3 mm | 24611/24612 |
| Märklin C track (slim) | 24720 | 12.1° | 236.1 mm | 24711/24712 |
| Trix C track | 62624 and slim 62720 | 24.3° and 12.1° | 188.3 and 236.1 mm | 62611 and 62711 |
| Märklin K track | 2260 | 22.5° | 168.9 mm | 2262/2263 |
| Märklin K track (slim) | 2275 | 14°26' | 225 mm | 22715/22716 |
| Märklin M track | 5207 | 24°17' | 180 mm | 5203/5204 |
| Märklin Z | 8560 | 13° | 112.8 mm | 8562/8563 |
| Minitrix | 14960 | 15° | 129.8 mm | 14954/14939 |
| Fleischmann piccolo | 9184 and 9185 | 15° | 111 mm | 9170/9171 |
| Fleischmann Profi | 6164 and 6165 | 18° | 200 mm | 6170/6171 |
| Piko A track | 55224 | 15° | 239.07 mm | 55220/55221 |
| Roco geoLine | 61164 | 22.5° | 200 mm | 61140/61141 |
| Roco Line | 42451 | 15° | 230 mm | 42442/42443 |
Minitrix also has a 30° double slip (14968), Märklin M track a 30° one (5128) and LGB a 22.5° one (12260). For Kato Unitrack, Hornby, Tillig and Tomix our catalogue lists no double slip. That says nothing about what the manufacturer ever made, only about what you can lay in TrackDrawer.
Roco geoLine stands out: our catalogue has no ordinary crossing for it, only the double slip. If you want two geoLine tracks to cross, it is either the 61164 or a bridge.
Where a double slip saves space: the turnout ladder
The classic spot is the throat of a station with three or more parallel tracks. A diagonal there links track 1 with track 3 and crosses track 2 on the way. With a plain crossing on track 2, a train on track 2 simply runs across the diagonal. Put a double slip in that spot and the same train can also take the diagonal, towards track 1 or track 3. Without a double slip you would need extra turnouts for that, and so extra length, which a station throat rarely has.
That it fits without fiddling follows from the geometry. The diverging road of the turnout on track 1 ends a certain distance to the side; half of the double slip's diagonal leg adds another stretch. Together they must make exactly the track spacing:
| System | Sideways from the turnout | Sideways from half the slip leg | Together | Track spacing |
|---|---|---|---|---|
| Märklin C track | 38.76 mm | 38.74 mm | 77.5 mm | 77.5 mm |
| Märklin K track | 32.32 mm | 32.32 mm | 64.64 mm | 64.6 mm |
| Roco geoLine | 38.27 mm | 38.27 mm | 76.53 mm | 76.5 mm |
| Piko A track | 30.94 mm | 30.94 mm | 61.88 mm | 61.88 mm |
For these four the ladder closes to a tenth of a millimetre. For Märklin M track, Fleischmann Profi and Roco Line the sum in our catalogue differs by 1 to 2 mm from the track spacing. Draw that ladder in TrackDrawer first: the check reports a closing error as soon as a joint is further out than the set tolerance (1 mm by default).
It costs little length, too. In C track the centre of the double slip lies 180 + 85.8 = 265.8 mm beyond the start of the turnout on track 1.
When you need one, and when you don't
A double slip makes sense when:
- you have run out of length. In a station throat, a fiddle yard or the fan in front of a loco depot you want as many routes as possible in as little length as possible.
- tracks cross anyway. Where a crossing cannot be avoided, a double slip turns it into a proper junction.
- you want a certain look. A station throat with double slips looks like a big station, even on a small baseboard.
A double slip makes less sense when:
- two regular turnouts fit. On an oval with a passing loop or a few sidings nothing crosses, so there is no need for one.
- you want to keep it simple. A double slip has more moving parts and more routes to set. In two-rail, the frog of many crossings and double slips has a dead section, and a short loco with few pick-up wheels can stall there. If a train runs badly across it, go through the points in train derails at the turnout.
Frequently asked questions
Is a double slip the same as a crossover?
No. A crossover is two ordinary turnouts between two parallel tracks that do not cross each other. A double slip sits where two tracks actually cross.
Does a double slip come in left and right?
For most systems in our catalogue there is one double slip per angle, because both roads are the same length: which one you treat as the main line makes no difference to the shape. Fleischmann has two in our catalogue, crossing to the left and to the right. What left and right mean for ordinary turnouts is covered in left, right and symmetrical turnouts.
Double slips in TrackDrawer
The Auto-designer does not put double slips into its variants; it works with your system's regular turnouts. You place a double slip yourself in the editor, at the open ends of your plan. The check then confirms that all four connections close, and in 3D you can send a train over every route. Let the Auto-designer suggest a station first, then replace a crossing or a couple of turnouts with a double slip.
