Closed Path
Unified Metropolitan Transit Control System
1. Problem
A metropolitan authority wants a unified passenger access control system covering all six transport modes simultaneously: tram, trolleybus, bus, suburban rail, metro, and funicular. The full scope includes validators on all vehicle types, ticket vending machines, card preparation workstations, inspector validators, driver information devices, a central database server, long-term tape archive, fare evasion detection, and a unified multi-modal ticket component. The network is heterogeneous — six independent subsystems with different hardware and protocols unified under a single ticket and central server.
The project sponsor sets the same condition as in Case 1: Production Release within the political and planning cycle — approximately 3–4 years. The team is confident. The question is whether the math agrees.
2. Choice
TA → PP → TP → WP → IM
Full cycle — Choice #1
Same choice as Case 1. The full lifecycle is required — this is a public infrastructure project with regulatory documentation obligations. No shortcut is available without abandoning compliance.
3. Target Stage
4. Mapping Note
For this project, 11 functions were selected via the Function Mapping Procedure (FMP). Full function composition is available inside the calculator.
5. Report View
Engineering resource allocation: TA=3, PP=3, TP=4, WP=20, IM=8 | Annual working time: 235 days/year per FTE
| Horizon | Stage | Product Stage | Labor (pd) | Team (FTE) | Time from Start |
|---|---|---|---|---|---|
| H0 | TA — Technical Assignment | Requirements Baseline | 1 020 | 3 | 1.45 yrs |
| H1 | PP — Preliminary Project | Prototype | 793 | 3 | 2.57 yrs |
| H2 | TP — Technical Project | MVP | 793 | 4 | 3.41 yrs |
| H3 | WP — Working Project | Release Candidate | 6 220 | 20 | 4.74 yrs |
| H4 | IM — Implementation | Production Release | 1 813 | 8 | 5.70 yrs |
| Total | 10 639 pd | — | 5.70 years | ||
| Comparison: Case 1 vs Case 2 — same method, different scale | |||
|---|---|---|---|
| Case 1 — Surface Electric Transport | Case 2 — Metropolis | Growth | |
| Functions | 5 | 11 | +120% |
| Total Labor | 3 541 pd | 10 639 pd | ×3.0 |
| WP team | 10 FTE | 20 FTE | ×2.0 |
| Total Duration | 3.36 yrs | 5.70 yrs | ×1.7 |
6. Decision
The current scope is a Closed Path under the selected assumptions. This is not a judgment about the team's capability — it is a mathematical result of three factors acting simultaneously:
- Volume: 11 functions vs 5 in Case 1 — labor grows 3×.
- Complexity: two High Complexity markers (Hard Real-Time + SCADA) and two Medium markers vs one of each in Case 1.
- Reuse: ≤20% vs 20–40% in Case 1 — six heterogeneous subsystems with a unified ticket have virtually no ready-made solutions.
The calculated route requires scope redesign: either implement the first subsystem as a standalone project (as in Case 1), or split the full system into sequential engineering phases with separate milestone gates.
7. Engineering Feasibility Analysis
The team says "we'll manage." The calculation says "no engineering resource allocation fits the target delivery window." This is not a forecast — it is a deterministic calculation based on fixed engineering parameters.
Starting this project in its current scope means committing to a scope revision in 8–10 months, after engineering resources have been allocated. The calculator makes this visible before commitment.
The calculated delivery route here separates the first subsystem from the full system scope — a phased approach: execute one subsystem first (Open Path), prove the technology, then expand scope in subsequent rounds.
Delivery model: Full Turnkey