What experience is there of materials for the spectacles of railway signals (red, green/blue and orange) from glass, or some form of translucent plastic?
My railway is 16mm in the garden, but as signals are intended for the human operators, I'm going for 1/12th scale signals.
(Yes, by modelling the 15 inch railways, the railway would also be 1/12th scale, but currently all my rolling stock is 16mm scale)