| Posted by J Moller on December 18, 2018 | |
ATSF and UP also used block indicators. ATSF had upper quadrant semaphores and UP had a disc with three circles that was vertical for block clear and horizontal for block occupied.
|
| Posted by Jeff Swanson on December 21, 2018 | |
Thanks for posting a few again Steve. I always love your candid shots and comments!
|
|