Trial Cards are Service Post Cards [M-26(a)] used to determine the relative advantage of alternative mail routes or to identify the cause of delay in the transmission of postal articles.
The reverse of a Trial Card contains the following printed columns:
- Source of receipt
- Remarks / Misconnection, etc.
- Manner of disposal
- Date stamp of the Office or Section
- Signature of the Head Sorting Assistant / Postmaster / Supervisor
These columns must be carefully completed by the Head Sorting Assistant, Postmaster, or Supervisor of every Office or Section handling the card. On reaching its destination, the Postmaster should also record the date and time of receipt of the mail carrying the card and the date and time of delivery before returning the card in a Service Cover to the issuing officer.
A Trial Card should be forwarded through the route, if any, marked on it and must not be included in any Station Bundle.