Chart shapes

Locomotive

Two thirds occupied, with one clean third empty

The rule: All ten inside two thirds, leaving an empty trine
Read through one planet: Yes

What it is

Every planet within 240 degrees, so exactly one third of the wheel is empty. It is the shape between a bowl and a splash: more spread than the first, more concentrated than the second.

The planet at the leading edge of the occupied arc is read as pulling the rest, which is where the name comes from. Which edge leads is not agreed between authors. This site takes the planet immediately after the empty trine in zodiacal order, which is the commoner convention, and says so rather than presenting it as settled.

How it reads

Drive. The tradition associates a locomotive with self-motivation and with a practical, applied cast of mind, and it is usually the most favourably written of the seven.

The reading is that the empty third supplies a direction: something is missing, the occupied two thirds are moving towards it, and the leading planet is at the front. That is a more specific claim than the bowl makes about its own empty half, and it is why the shape reads as active rather than as self-contained.

The leading planet is read the way a bucket handle is, though less absolutely. It sets the manner of the drive rather than carrying the whole chart.

Where the reading sits

The leading planet at the edge of the occupied arc. It is read as setting the manner of the chart, though which edge leads is a convention rather than a settled point.

How common it actually is

Less common than it first appears: 14.7 per cent of charts, about one in seven. Sorting by total span alone puts it at nearly twice that, because charts occupying two thirds of the wheel in two separate clumps get swept in. Those are seesaws, and excluding them is what brings the number down to what a continuous train of planets actually is.

What to watch for

The favourable write-up. This shape attracts warmer language than the other six, and there is nothing in the geometry that earns it.

Is your chart a locomotive?

The birth chart tool names your shape along with the span it occupies and the widest empty arc. Bear in mind that the thresholds are a convention rather than a fact, so a different tool may reasonably give you a different word for the same chart. The hub prints the exact numbers this site uses.

Draw your birth chart free The thresholds, and how much they matter Aspect patterns