This localized interlocking mechanism allows crews to manually operate nearby turnouts and signals without needing a remote dispatcher. They are typically kept locked and are only released by the mainline dispatcher when a local train needs to shunt cars into a siding or branch.
Heard on the job
Dispatch, we need a release on the ground frame at mile 42 to set out these bad order hoppers.
Do not mix it up with
- Lever frame: A lever frame is usually inside a signal tower, while a ground frame is outdoors at track level.