Assembly Shift, Overtime & Transport Optimisation
Two assembly lines, one van fleet. How could the two-shift line take on overtime without extra van runs or a fatigue-heavy night?
Open full image ↗The challenge
At Atlas Honda there were two motorcycle assembly lines on different shift patterns. Line 1 ran a single day shift. Line 2 ran two shifts back to back: a day shift, then a night shift that started as the day shift ended. Both lines relied on the same contracted transport vans.
Overtime caused two separate problems:
- Extra van runs. On overtime days Line 1 stayed on past its normal finish, but Line 2’s day shift still left at the normal time. That meant one set of van runs for Line 2 at the normal finish and another for Line 1 when its overtime ended.
- Line 2 couldn’t take overtime. A normal-length extension on the night shift finished at a time the vans couldn’t serve: they couldn’t take the night team home and still be back for the morning shift start. The only extension that matched the morning vans was much longer than the usual overtime block, and that wasn’t workable because of fatigue.
Adding vans would have fixed the transport side at a recurring cost, but not the fatigue. The question was whether rescheduling could fix both.
Mapping the constraint
I laid the two lines’ shift patterns and the van cycle side by side rather than treating transport as a separate problem:
Together they showed the waste: van runs at different times for teams that could have travelled together, and a night-shift finish that never lined up with a van arrival.
Five options compared
| Option | What it gets right | What goes wrong |
|---|---|---|
| No overtime on Line 2 | Simplest | Line 2’s extra output is lost |
| Normal overtime on the night shift | Usual overtime length | Finish doesn’t match the vans, so the morning pickup can’t be met |
| Long overtime on the night shift | Finish matches the morning vans | Too long for one team: fatigue, safety and quality risk |
| Add van runs | Operationally simple | Recurring cost, and the two lines still travel separately |
| Split Line 2’s overtime and align it with Line 1 | Overtime on both lines with the existing fleet | The night shift reports later on overtime days, so it needs clear communication |
The proposed configuration
Line 1 kept its normal overtime pattern. On Line 2, I split the overtime between the two shifts and moved the changeover to Line 1’s overtime finish:
Each Line 2 team works part of the overtime instead of one team carrying all of it, and every van movement serves two groups on the same routes: the run that takes both day teams home brings the night shift in, and the run that brings the morning shift in takes the night shift home.
Why it balanced better
- Line 2 can take overtimeIts extra output was previously blocked by the van cycle.
- Fatigue kept in checkNo team works the long block; each shift carries a share.
- Fewer van runsLine 1 and Line 2’s day shift go home together instead of on separate runs.
- No extra fleetEvery run carries a team in both directions, so the existing vans and routes cover the new pattern.
Presentation and outcome
I turned the analysis into a cost-benefit proposal and presented it to senior plant leadership. It showed both problems could be solved by retiming Line 2’s changeover rather than adding vans, and it named the main implementation risk: the night shift’s later reporting time on overtime days needs clear communication and schedule discipline.
Of the options assessed, splitting Line 2’s overtime and aligning it with Line 1 gave the best balance of output, fatigue and transport cost.
Shift times, overtime hours, transport routes, fleet sizes and costs are internal and not published here. The screenshot is a recreation with illustrative data, not the original file.
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