Lever 16 is pulled to reverse the main to main crossover. The lock in channel 2 is driven to the right, driving bars 1 and 3 to the right (which lock levers 3 and 1 respectively). The lock in channel 3 is driven right, driving the condition piece on tappet 17 and as 17 is reverse, this drives the lock to the right of 17 to the right (which locks 4 and 8 normal). This locking is released again once 16 is fully reversed. Click here to pull 33.