Table: campbeltown and machrihanish light railway
Question: How many locomotives built by Andrew Barclay & Co were converted from 0-4-0 to 0-4-2?
Step 1 (Operation, Indexing): builder
Step 2 (Operation, Filter): builder
Step 3 (Operation, Filter): type
Step 4 (Reasoning, Aggregating): SUM, works number
Answer: 269