What Is Transit Time in Production Scheduling?

Transit time is the number of whole days parts take to physically travel between two operations, such as an outside vendor for heat treatment or plating, counted either as flat calendar days or as working days only. It models real transport delay rather than machine work, which is why it is measured in days: once parts leave the plant, hours on your shift clock stop being the right unit. The receiving operation cannot begin until the parts return and a shift is open.

EDGEBIC by User Solutions supports both calendar-day and working-day counting on any step. This article defines the term and the counting modes. The full composition order, where transit combines with queue and flow, is in how EDGEBIC handles queue and transit times.

How It Works

You set transit as a whole number of days on a routing step, and choose whether it counts calendar days or working days. Calendar counting, the default, adds raw days including weekends and holidays, because an outside vendor operates on its own calendar and your shift schedule is irrelevant to how long the parts are away. The result may land on a weekend, and the engine simply searches forward from there for your next open slot.

Working-day counting is stricter. It counts only days that have at least one active shift, so weekends and plant holidays are skipped and do not consume transit days. A three-day working transit therefore stretches across the calendar to skip a weekend. After working-day transit, the downstream step lands at the end of the last shift on the final counted working day, not at midnight, so the receiving operation waits until the plant re-opens.

Transit is distinct from queue time, which is shift-aware hours for waiting inside the plant. Both can apply to the same step, and they compose in a fixed order, so a part can queue for inspection and then ship to a vendor on one routing without ambiguity.

A Concrete Example

Think of the three-day delivery between your plant and the plating vendor. The parts are on a truck and at the vendor; your shifts have nothing to do with how long that takes.

Take a CNC step that ends Thursday 12:00, feeding a post-heat-treatment inspection, with three transit days. In calendar mode, the engine adds three raw days to Thursday 12:00, landing Sunday 12:00. Since there are no Sunday shifts, it searches forward and finds the next open slot Monday 08:00. In working-day mode with a Monday-to-Friday plant, the engine counts Friday as day one, skips Saturday and Sunday, counts Monday as day two and Tuesday as day three, and returns end of shift Tuesday. That is a net five calendar days but exactly three working days. For a Monday-to-Friday shop the practical Monday-morning result is often the same, so the difference matters most when the transit crosses multiple weekends.

When the Counting Mode Actually Matters

For a Monday-to-Friday plant, calendar and working modes often resolve to the same practical slot on a short transit, because both land the parts back on a Monday morning either way. The difference grows with the length of the transit and the number of weekends it crosses. A three-day calendar transit starting Thursday lands Sunday, which becomes Monday when the plant re-opens. The same three days in working mode counts Friday, Monday, and Tuesday, landing end of shift Tuesday, a net five calendar days.

So the mode matters most for longer moves and for plants with unusual calendars. A vendor that plates over a holiday week is best modeled with calendar days, because the vendor ignores your closures. An internal truck run that only happens on working days is best modeled with working days, because a weekend genuinely does not advance it. When in doubt, ask whether the clock keeps running while your plant is closed. If it does, use calendar days. If it stops, use working days. That single question resolves most transit configuration decisions.

How EDGEBIC Uses It

Transit is a field on a routing step, applied after any queue and flow effects on that step. The Gantt shows the downstream operation held back by the travel delay, and because you choose the counting mode, an outside vendor and an internal working-day move are modeled correctly on the same routing.

Transit days are also the foundation for multi-plant routings, where an operation at one site feeds an operation at another. The manufacturing glossary covers the related terms, what is queue time explains the shift-aware sibling, and multi-plant scheduling with transit times shows transit connecting operations across locations. The report that audits which counting mode each routing step is actually in, and catches working-day transit falling back to calendar days, is the transit days configuration check.