The tunnel mail list records a packet when it leaves Underway. The ridge book records it when a carrier accepts the seal. A sender could see two totals but not which handoff accounted for a missing mark.
The new list repeats one seal number at dispatch, at the tunnel exit and at the ridge station. It does not reveal what a packet contains. It gives the two route offices a shared reference for finding where the transfer record stops.
That difference matters when a packet changes hands between the tunnel and surface crews. Each office can keep its own log while preserving a common route history.
The trial will end after one full mail rotation. The route board will publish the number of packets with all three marks before deciding whether the shared seal field becomes standard.
The route offices closed this docket by adopting the shared seal number for dispatch, transfer and arrival. The next file will count packets from a new mail rotation.
