RailPlan Algorithm lab

Why did this work move?

Change a constraint. Watch the schedule respond.

Loading the teaching model…
Six work orders over eight weeks. Select a work order to inspect its placement. Each filled cell is one access.
Work orderW1W2W3W4W5W6W7W8
The model is loading. No schedule has been calculated yet.
Used / available
Scheduled accessAfter due weekDue weekUnavailable

Six work orders. Nine required accesses. Eight weeks.

— / 6work orders complete
— / 9accesses scheduled
weighted delay · lower is better

Every required access must fit. The model never drops work to improve its score.

How CP-SAT works

A three-step walkthrough · not a live search trace

CP means constraint programming; SAT means satisfiability. Together, they turn scheduling into precise choices, rule out impossible combinations and search for the best valid plan.

Turn a planning question into a mathematical model.

    In this demo

    Solver result, checks and model limits

    Result evidence

    Run the solver to inspect its result.

      What this model includes

      Six fabricated work orders, a shared weekly access pool, full workload, optional predecessors and a weighted-delay objective. At most one access per work order per week; accesses can be nonconsecutive.

      Where the model stops

      This is an eight-week teaching model, not the official PS1 solver or scoring formula. It omits track geometry, safety buffers, Live mirroring, interchange rules, legal work mixes, co-sharing, contract caps and ECLO policies. “Optimal” applies only to this model.