This crossing bell is typical of those used at railroad crossings.� More modern bells have a similar shape but are roughly two-thirds the size.� Earlier bells were also made in a teardrop shape having a somewhat pointed top.

Above.� Circuit drawing from inside back cover which shows how the circuit works.� With no voltage applied, the bell contact is closed.� Applying voltage causes the electro-magnet coil to draw the moving arm toward the coil which opens the bell contact.� This in-turn de-energizes the magnet coil causing the moving arm to fall away from the coil, closing the bell contact and restarting the cycle.� The number of strokes can be adjusted by increasing or decreasing the gap of the bell contact.� The discharge rectifier is needed to protect the power supply from voltage spikes caused by opening the bell contact and de-energizing the magnet coil..

Left.� Open back showing the electro-magnet coil (light red), bell contact switch and moving arm (silver) which through a series of connecting arms attaches to a bell striker on the other side of the case.� The coil and switch operating together cause the moving arm to swing from left to right causing a corresponding movement of the bell striker on the other side of the case.� The dark red piece holds the assembly to the back of the case and does not move.� The bell striker is directly attached to the shaft going through the back of the bell case.