Ready Spec
Rail Passenger Access System — Ready Spec
1. Problem
A suburban rail operator is replacing an aging passenger access control system. The operator has been running the predecessor system for over 10 years — requirements are well-known, documented, and handed to the vendor as a complete Technical Assignment prepared by the customer's internal team together with an external business analyst. TA coverage: ~85%.
Since the customer's team fully understands the domain and the conceptual design is inherited from the existing system, there is no need for a Preliminary Project (PP) stage — the concept is already established. The vendor starts directly at TP (Technical Project).
The question: how much does the ready TA and skipped PP actually save — and what are the conditions for this saving to be real?
2. Choice
TA(0) → TP → WP → IM
Choice #2 — TA excluded, PP skipped
TA is present in the configuration with Labor = 0: the stage is not excluded from the lifecycle — its labor is zeroed by the flag "TA provided by customer." PP is skipped entirely — the concept is defined by the existing system. The vendor scope starts at TP.
3. Target Stage
First deliverable: H2 (MVP) at 0.77 yrs — the fastest first artifact among all full-cycle cases in this collection.
4. Mapping Note
For this project, 6 functions were selected via the Function Mapping Procedure (FMP). Full function composition is available inside the calculator.
5. Report View
Team configuration: TP=3, WP=8, IM=3 | Fund: 235 days/year per FTE | Delivery model: Implementation Partnership
TA: provided by customer, Labor = 0. PP: skipped — concept inherited from existing system.
| Horizon | Stage | Product Stage | Labor (pd) | Team (FTE) | Time from Start | Scope |
|---|---|---|---|---|---|---|
| H0 | TA — Technical Assignment | Requirements Baseline | 0 | — | — | Customer |
| H1 | PP — Preliminary Project | Prototype | — | — | — | Skipped |
| H2 | TP — Technical Project | MVP | 544 | 3 | 0.77 yrs | Vendor |
| H3 | WP — Working Project | Release Candidate | 1 895 | 8 | 1.78 yrs | Vendor |
| H4 | IM — Implementation | Production Release | 621 | 3 | 2.66 yrs | Vendor |
| Vendor Total | 3 059 pd | — | 2.66 years | |||
| Full cycle (TA + PP + TP + WP + IM) | Case 5 — Ready Spec | Saving | |
|---|---|---|---|
| Total Labor | 3 409 pd | 3 059 pd | −350 pd (−10%) |
| Total Duration | ~3.5 yrs | 2.66 yrs | −~0.84 yrs |
| First artifact | H1 Prototype at ~1.2 yrs | H2 MVP at 0.77 yrs | First artifact 36% faster |
6. Decision
Accept the configuration — with a mandatory TA review on entry to TP. Coverage of 85% is a good indicator, but rail systems frequently contain edge cases in tariff rules and exception flows that are not captured in the main documentation stream. If the review reveals gaps — log them as TP risks with a buffer, not as grounds to return the full TA.
The saving here is real and measurable: 350 pd and ~10 months. But the risk does not disappear — it shifts to the quality of the incoming document. This is the correct trade-off when the customer has genuine domain expertise.
7. VC Interpretation
A ready Technical Assignment is not just a convenience — it is a measurable financial asset. 350 pd of saved labor and ~10 months of shorter contract duration translate directly into reduced burn rate and faster time to first deliverable.
The first artifact (MVP at H2) arrives at 0.77 years — the fastest first checkpoint among all full-cycle cases in this collection. For the investor, this means the first verification of technical progress happens in under a year.
The risk is structural: the saving is only real if the TA is complete. A TA review before TP starts is not optional — it is the condition under which the 350 pd saving materializes rather than migrates into unplanned TP rework.
Delivery model: Implementation Partnership | Patent Pending — Ukraine