It is likely that access to Foley Park sidings was achieved by a ground frame, or possibly two ground frames located at opposite ends of the sidings, unlocked by the Kidderminster Junction - Bewdley South token. There may also have been an intermediate token machine, to allow trains to be shut in.
After the closure of the Bewdley-Kidderminster line, two two-lever ground frames were installed at an unknown date on the single line adjacent to the sidings, used to control access between BR and the SVR. It appears they each controlled a single trap point and associated FPL, with an SVR GF controlling traps in one direction, and a BR GF controlling traps in the other.
References
A photograph showing a special train proceeding past the BR/SVR ground frames, C E Steele, 1979. Photograph uploaded to the RMweb forums. Link. Accessed 09/01/2015.