Journey Split

Key point

multimodal ETAs

The same hours, sorted two ways. Moving is the time the legs take. Waiting is the time the cargo sits at a hand-off, and it grows when the next leg leaves on a schedule.

A truck, a ship and a train carry cargo from Shanghai to Chicago. One total, 484 hours, hides where the time went. Part of it is cargo moving. The rest is cargo waiting, and the two fail in different ways: a schedule forecasts the moving time, and a terminal’s queue moves the waiting.

Set the legs, or pick a preset. The tool calls multimodalETA for the ETA and the two totals, and scheduleDelivery for the instant each leg leaves and arrives. diffUtcAsDuration measures each wait. The top ribbon puts the legs in order, with each wait where it falls. The bottom ribbon gathers the same segments: moving at the left, waiting at the right. A table under them lists each hand-off.

1. Set the legs

A truck, a ship and a train take cargo from Shanghai to Chicago. The ship sails at a scheduled 14:00 on 12 June, so the cargo waits for it after its handling time ends: 6 hours of handling, then 42 more for the sailing.

A truck, a ship and a train take cargo from Shanghai to Chicago. The ship sails at a scheduled 14:00 on 12 June, so the cargo waits for it after its handling time ends: 6 hours of handling, then 42 more for the sailing.

The same legs, but the ship has no scheduled departure. Each leg leaves when the handling time before it ends, so the only waiting is the handling.

Two legs. The cargo arrives at 10:00 and needs two hours of handling, but the second leg is scheduled to leave at 11:00. The library returns no journey.

A train leaves New York at 20:00 on the night before the clocks spring forward. It runs for 10 hours, so the wall clock shows 11. The moving time counts the 10 hours that passed, then two hours of handling, then 3 hours by truck.

For a published local first departure with no offset or zone of its own.

Durations are ISO 8601: PT46H is 46 hours, PT2H30M is two and a half hours, P11D is 11 days. Handling after is the time the cargo needs at the hand-off before the next leg may leave.

① Truck · PT6H → Shanghai

DurationDepartsHandling after optional

② Ship · P14DT6H → Los Angeles

DurationScheduled departure optionalHandling after optional

③ Rail · PT52H → Chicago

DurationScheduled departure optionalHandling after optional

2. Moving and waiting

ETAno result

Movingno result

Waitingno result

As it happens

Gathered

• moving, one colour for each leg
• handling
• waiting for the scheduled departure

Arrives	Handling	Ready	Departs	Waited

Open these legs in the Delivery Scheduler

3. What multimodalETA returns

 

The words. On screen, handling is the time you state for a hand-off, the dwellAfter of a leg. It is how long the cargo needs there before the next leg may leave. Waiting is the time the cargo is actually at the hand-off, which the library calls totalDwell: each leg’s departure minus the previous leg’s arrival. Waiting is handling plus any wait for a scheduled departure. Moving is every leg’s duration added up, which the library calls totalTransit. The printed calls keep the library’s names.

A scheduled departure is waiting that handling does not explain. A leg that names its own departure leaves then, not when the handling ends. If the time is before the handling ends, the cargo is not ready, and the library returns null. If it is after, the cargo waits for it. The chip under a wait names both parts, and the two ribbons draw them with different hatches.

The ribbons are drawing. The library gives every time. The tool places a segment where its two instants fall, and a test checks that the moving segments add up to totalTransit and the waiting ones to totalDwell for every preset. The tool has no drag handle: it is a form and presets.

const legs = [
  { departure: "2024-06-10T08:00:00+08:00[Asia/Shanghai]", duration: "PT6H", timeZone: "Asia/Shanghai", dwellAfter: "PT6H", mode: "truck" },
  { departure: "2024-06-12T14:00:00+08:00[Asia/Shanghai]", duration: "P14DT6H", timeZone: "America/Los_Angeles", dwellAfter: "PT36H", mode: "ship" },
  { duration: "PT52H", timeZone: "America/Chicago", mode: "rail" },
];

multimodalETA(legs); // { eta: "2024-06-29T23:00:00-05:00[America/Chicago]", totalLegs: 3, totalTransit: "PT400H", totalDwell: "PT84H" }

diffUtcAsDuration("2024-06-10T06:00:00Z", "2024-06-10T12:00:00Z", "hours"); // "PT6H"
diffUtcAsDuration("2024-06-10T06:00:00Z", "2024-06-12T06:00:00Z", "hours"); // "PT48H"
diffUtcAsDuration("2024-06-10T12:00:00Z", "2024-06-12T06:00:00Z", "hours"); // "PT42H"
diffUtcAsDuration("2024-06-10T00:00:00Z", "2024-06-30T04:00:00Z", "hours"); // "PT484H"

The truck arrives at 2024-06-10T06:00:00Z and the ship sails at 2024-06-12T06:00:00Z, so the first wait is PT48H. The cargo is ready at 2024-06-10T12:00:00Z, so PT6H of those hours are handling and PT42H are the wait for the sailing. Leave the ship leg without a departure and totalDwell falls to PT42H: the 6 hours and the 36 hours of handling, and nothing else.

Across a clock change. totalTransit is exact time. A train that leaves New York at 20:00 on the night before the clocks spring forward and runs for 10 hours arrives at 07:00, when the wall clock has moved 11 hours. The tool counts the 10 hours that passed. The preset adds two hours of handling and three hours by truck: totalTransit is PT13H, totalDwell is PT2H, and the ETA is 2024-03-10T12:00:00-04:00[America/New_York].

Worth trying: the ship’s sailing moved a week later — totalTransit stays PT400H and totalDwell grows to PT204H, because the cargo waits seven days for the ship. Then the same ship sailing at 10:00 on the first day — it leaves before the truck’s handling ends, so the result is NO SIGNAL. And two days of handling instead of a sailing — the totals match the scheduled sailing’s, PT400H and PT84H, but the chip under the first wait now names handling alone. The Delivery Scheduler shows the same legs leg by leg, and the link under the table opens them there.

Reference: multimodalETA gives the ETA and the two totals, scheduleDelivery gives every leg’s time, and diffUtcAsDuration measures between two Z instants. The rules are in Intermodal: B/L Dates and Multimodal ETA and Transport: Multi-leg Scheduling.