A key holder located at the visible base of levers in a frame of NSWGR in the 20th century.
In a primary mechanical lever frame located in a signal box, such holders held an Annett key for unlocking particular secondary frames around the yard. A key could only be released from a holder by pulling its lever off normal, thereby engaging some safeworking interlocking that prevented some other levers in the primary frame from being altered. The lever from the holder of which a key was removed could not be restored to normal until the key was returned.
In the case of a secondary yard frame with a locked lever, no lever in the frame could be pulled off normal until the locked lever was unlocked by a key and pulled off normal.
Intended for use as a discretionary mesh to appear on selected levers of the assets:
<kuid2:368725:90030:4> NSWGR mechanical lever frame for a signal box, 18-28 levers, for avatar operation
<kuid2:368725:90044:2> NSWGR mechanical lever frame for a station yard, 1-5 levers, for avatar operation
<kuid:368725:90053:1> NSWGR mechanical lever frame for a signal box, 8-18 levers, for avatar operation