Two histories set down the page together and compared year by year: on one track the observatory itself, on the other the science going on around it, with the shared year between them. Six years, a title and one line per side. Core blocks only: core/group, core/columns, core/column, core/heading, core/paragraph.
The signature moment
Two rails, one clock
The signature is that there are two records and one set of dates. Every other timeline in the catalogue runs one story down one line. This one puts a second story beside it on the same six years, so the section is not a chronology, it is a comparison: what the station did, against what the field was doing while it did it. The year column is the only thing the two tracks share, and it is what makes the row a row.
That is why the two hairlines are the composition rather than decoration. Each track has its own rail, so the eye can follow one side down the page without losing the other, and the copy on each side is set against its own rail: track A is right-aligned to its border-right, track B is left-aligned to its border-left, so both columns of type face the centre and the year sits in the channel between them. Two lists side by side would read as two lists. Facing them at a shared date is what turns them into one argument.
The rails carry the whole composition, so they are currentColor and never an accent: they cannot resolve to nothing, they follow your text colour, and they invert with the section if you recolour it.
How the rails are built, and why they are unbroken
There is no separator block and no rail element. Each row is a core/columns of three, and the two track columns each hold a group with a single-side border. Consecutive rows carry no vertical gap at all: the enclosing section sets blockGap: 0 and every row's core/columns sets blockGap.top: 0, so those borders touch and form two continuous lines. The spacing between rows is each row's own top and bottom padding, never the gap. That is why the rails are two lines rather than twelve dashes, and it is why adding a year cannot break them.
Unlike timeline-rail, the rails here do not run past the ends. They start at the first year and stop at the last, because a comparison is bounded by the dates it compares: the span is the point, and an overhang would claim a comparison that the section does not make.
The header row is part of the design
The two tracks are labelled once, in a header row above the entries: small uppercase wide-tracked labels sitting over their own columns, with Year centred between them. It is a table head, not a caption, and without it the reader has to infer from the copy which side is which. Its labels carry the same side padding as the entry groups below, so each label sits over its track's type rather than over the column box.
What it inherits from your theme
- The typeface. No font family is stated anywhere.
- Your colours.
basefor the ground,contrastfor the type, both ending on a colour WordPress guarantees. Both rails arecurrentColor. - Your spacing scale. Every gap, including the row rhythm and the space under the header row, is a spacing preset, so a theme with a generous scale gets a looser record.
What it decides for itself
- Full bleed with a 1240px measure.
- The 42/16/42 split, which gives each track about 500px at 1240: enough for a title and a sentence, not enough for a paragraph. The density is the constraint and it is on purpose.
- The facing alignment. Track A right, track B left. This is the decision that makes the comparison legible, so change it last.
- The year at display size against entry titles a third of it, so the shared date reads as the spine of the row rather than as a third entry.
- A closed span. The rails begin and end with the record.
What to change first
- The two track labels. They name what is being compared, and everything else in the section depends on the reader getting them in one glance. Keep them short: they stack onto their own lines at 390.
- The six years. Plain text, so
1953,Spring 1953orQ1all set. Anything much longer than four characters wants a wider middle column, and the middle column is where the two rails meet. - The entries. A title and one line each. Two lines still fit; a paragraph turns the comparison back into two documents. Duplicate a whole row to add a year, and check that the row you copied is not the first or last one if you later change the end padding.
- The heading and the lede. The lede says what the two tracks are. If you change the tracks, that sentence is the first thing to rewrite.
- The number of rails. Ship the base where both records are equally the subject, and
parallel-single-railwhere the dates are the subject and the two tracks are commentary on them.
What happens at 390, honestly223 words
The three columns stack, which is core's default below 782px and the right answer here: at 390 a three-column row gives each track about 150px, which ladders a title into one word per line. So the row unfolds into entry, year, entry, and the six rows become an interleaved sequence.
Two things follow, and both are deliberate:
- The rails stop being continuous lines. Stacked, each track's group is a full-width block with the year between the pair, so the borders no longer touch. What survives is a per-entry mark: a right-hand rule with the type pushed right for the station, a left-hand rule with the type at the left for the field. The alternation is what tells you which record you are reading, and it is legible without the labels being repeated.
- The station entry arrives before its year. The year is a hinge between the two entries it dates rather than a heading above them. It reads as a pair of facts and the date they share, which is the same claim the desktop row makes, in the only order three stacked columns can be read in.
The header row stacks too, into three lines of small caps. That is the one place the phone layout is weaker than the desktop one, and it is why the labels are short.
How the entries are structured136 words
Each row is one core/columns with three core/column children:
| Column | Width | Holds | |---|---|---| | Track A | 42% | a group with border-right, holding an h3 and one right-aligned paragraph | | Year | 16% | one centred paragraph, its margin-top matching the tracks' padding-top so the three tops line up | | Track B | 42% | a group with border-left, holding an h3 and one left-aligned paragraph |
The border is on a group inside the column, never on the column itself, so the pattern does not depend on core/column border support at the 6.6 floor. Both headings state their own text colour, because a theme's heading element style beats a colour inherited from the section group and that is how a title lands the same colour as its ground.
The variation: one rail, two tracks86 words
parallel-single-rail moves one axis, composition, and nothing else. The two hairlines collapse into a single spine near the centre and the years are hung on it; the track columns lose their borders entirely and become 44% each. The section stops being two records kept side by side and becomes one line of dates carrying two commentaries, one either side. The copy, the years and the labels are identical to the base, so the switcher asks one question: is the comparison the subject, or are the dates?
Notes80 words
- Core blocks only. No plugin, no script, no separator, no image.
- Every colour is a fallback chain ending on a guaranteed colour, and every rule is
currentColor. - Entry copy is set at a
clamp()with a 15px floor rather than a core preset, because core'ssmallis 13px in a theme with no size scale. - It is a history, not a process: nothing is numbered, nothing is counted down, and nothing asks the reader to act.
Display type18 words
Off the theme's ladder on purpose, because the size is the composition:
- paragraph at clamp(1.25rem, 2.2vw, 2rem)
The markup
Core block markup and nothing else. Copy it, then paste it straight into the block editor: WordPress reads the delimiters and rebuilds the blocks.
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