A historic lineside apparatus consisting of a retractable arm that suspended a mailbag next to the tracks. As a railway post office car passed at speed, a catcher arm on the train would snatch the bag from the traductor. A spring mechanism then immediately retracted the empty arm away from the kinematic envelope to prevent it from striking subsequent cars.
Heard on the job
The station agent hung the outbound canvas sack on the traductor just as the night mail whistled for the crossing.
Also heard as
- mail crane