Sentence:  In addition to its work on longwall faces, the A.B. Fifteen has been adapted for shortwall work either as <WSD>undercutter</WSD> or as overcutter, particular care having been taken to give it increased manoauvrability by the provision of special pulleys, and increased mobility by the addition of a tilting underframe. 
Meaning of the word marked with <WSD> tags:  A device for cutting into rock walls from below.