CCTV Level Crossing Picture Timer relay circuit

[merlin89]

Can somebody explain the function of the attached circuit which forms part of the CCTV Level Crossing Picture Timer relay circuit (IRSE Railway Control Systems page 176). My theory is that when the signaller pushes the picture button which releases the PICTURE.SR the PICTURE Timing Relay will also drop, a 47 second AGASTAT Timer also starts. After 47 seconds has elapsed and provided the PICTURE.SR has picked the PICTURE Timing Relay will also re-energise. Not too sure about how the AGASTAT timer works and I think inductor in series with capacitor with the Picture JR.

Much appreciated
Ian