Definition · Applied example · Translation review candidate
Two-Rail and Public–Private Asset Sharing
This page is an applied example. The field-independent minimum definition of Two-Rail is the Two-Rail Kernel. This page applies Two-Rail to the separation of public and private accounting and cash flows. Rail-P (the public rail) and Rail-K (the private rail) are fiscal-context implementations of the Kernel's public and private rails.
→ Two-Rail Kernel (definition) · → Two-Rail entry page (Japanese reference)
An applied design that records and discloses public-side and private-side cash flows separately, without mixing them: the application of Two-Rail to public–private accounting.
When public bodies and private operators jointly operate public facilities or services, accountability to residents breaks down if it becomes unclear what is public expenditure and what is private profit. Two-Rail is an accounting and record-keeping design for that problem.
The problem it addresses
When private operators participate in public facilities or administrative services, conventional designs can allow public and private revenues and expenses to become mixed.
- Public funds (tax revenue and expenditure) and private revenue are recorded in the same ledger
- It is impossible to verify how much a private operator reduced costs through efficiency
- An external auditor cannot determine which figures belong to the public side
As a result, explanation to residents becomes difficult, and questions from assemblies, auditors, and the press become harder to answer.
The Two-Rail approach
Two-Rail separates the recording of revenues and expenses into two rails from the outset.
Rail-P (public rail)
The rail for revenues and expenses attributable to the public side, including expenditure reductions, shared-use revenue, and returns to residents. Aggregates disclosed externally are produced from this rail.
Rail-K (private rail)
The rail for revenues and expenses attributable to private operators, including sales, fees, and costs. Individual contract terms remain private, while aggregates are disclosed.
Why separate the rails
Prohibiting transfers, offsets, and mixing between the two rails preserves the ability to verify later whether public funds were converted into private revenue or private costs were reassigned to the public side.
What public–private asset sharing means
A framework for joint public–private operation of public facilities, equipment, and spaces, built on Two-Rail.
Examples include the following.
- Joint reservation and operation of meeting rooms or multipurpose rooms in public facilities with a private operator
- Increasing the utilization rate of public equipment while disclosing the resulting reduction in public expenditure
- Allocating part of private revenue to resident returns or the maintenance of public-priority access
Under this framework, contracts with private operators apply a No-Net-Burden principle: costs must remain within the value of the effects produced, and the net burden on the public side must be zero or less.
Boundary between public and private information
Two-Rail clearly separates information that is disclosed from information that remains private.
Disclosed information (aggregated and delayed)
Total expenditure reduction, total returns to residents, aggregated private fees, and complaint counts. Each is disclosed subject to a 90-day delay and small-group protection.
Information kept private
Individual contract terms, transaction details by vendor, and personally identifiable information.
This boundary is fixed by design and cannot be changed at an operator's discretion.
Position within C³
What Two-Rail does
- Separates and records public-side and private-side revenues and expenses
- Preserves a state that third parties can verify later
- Makes the basis for disclosed aggregates auditable
What Two-Rail does not do (non-goals)
- Automatically decide permission to use or reserve a facility
- Select or evaluate private operators
- Set policy priorities
- Disclose individual contract terms
Two-Rail is not a mechanism for making decisions. It supports the recording and disclosure of decisions.
Related concepts
- What is C³ →
Overview of the institutional operating-system concept.
- Verified Web →
How definitions, specifications, and updates are published.
- C³ ITS API (Japanese reference) →
The gate-control layer for AI agents.
Time layer
doc_id: DEF-TWO-RAIL-001
Document lineage ID: C3-DEF-TR-01
Version: v0.1
Status: DRAFT
Last Updated (source): 2026-04-19
Source semantic revision: sr-0.1.0
Governance identity boundary
C3-DEF-TR-01 is this translation group's document lineage ID. It is not a Registry snapshot Verify ID and it does not issue or inherit a C3-REF value.
This English review candidate has no Registry binding of its own.