Here are some more photos following the addition of the Eemeck electrical releases.
The active element of an electrical release is seen in the photos as a vertical brass tube. This is the Actuator. At the top is a spring-loaded brass piston. This is drawn down when an electrical current is passed through a muscle-wire that is fixed at the bottom of the actuator and to the piston.
The actuator is normally de-energised and will latch the tappet of a lever when the lever is in the state from which it much be electrically released. When it is possible to release a lever, the push-button on the release panel lights. Pushing the button then releases the tappet.
You will note that Lever 7 will latch in either the normal or reverse position and must be electrically released for movement in either direction.
The other two electrically released levers are 4 and 10. These latch only in the normal position and must be electrically released (by line clear from the adjacent signal box) before either can be reversed to clear the starting (section) signal.
Note that there are multiple versions of release assembly. Each assembly may relate to either the odd-numbered tappet or the even-numbered tappet for each pair of levers, or to both. In this frame there are no paired releases. You will also note that the release push-button for an odd lever is higher and to the left of the panel, whilst the release PB for an even lever is lower and to the right.
Further, there are variants that allow a lever to be latched in the central position. This requires two actuators for each such lever, so it is possible to have four actuators on one release assembly. When levers are latched in the central position, there are two release PBs for each lever - one to release the lever to be pulled, the other to release the lever to be pushed.
