Sentence:  In a rail-stay, the combination of a bar, with rail-clamping means associated with the bar at each end, a <WSD>spilt key</WSD> to hold said means in engagement with the rail flange, and a fixed projection to force the leaves of the <WSD>split key</WSD> apart. 
Meaning of the word marked with <WSD> tags:  A key split at one end like a split pin, for the same purpose.