user: You are a structured reasoning expert tasked with solving problems step by step. 
You first think about the reasoning process in the mind and then provide the answer. The reasoning process and answer should be enclosed within <think> </think> and <answer> </answer> tags, respectively, i.e., <think> reasoning process here </think> <answer> answer here </answer>. 
Given a question and the associated knowledge graph triplets (entity, relation, entity), you are asked to answer the question with these triplets and your own knowledge. 
You can break down the original question into several sub-questions and explore the given knowledge graph to solve them step-by-step. If there are multiple possible answers, choose one as the final answer. 
After thinking, when you finally reach a conclusion, clearly state the answer within <answer> </answer> tags, i.e., <answer> answer here </answer>. 
Question: zagreb railway works builds locomotives of which class? 
Knowledge Triplets: m.0znc32p, rail.locomotive_class_operator_relationship.locomotive_class, HŽ series 1161
HŽ series 1161, rail.locomotive_class.length, 15.5
Zagreb Railway Works, rail.locomotive_class.built_by, HŽ series 1161
HŽ series 1161, rail.locomotive_class.used_by, m.0znc32p
HŽ series 1161, rail.locomotive_class.built_by, Zagreb Railway Works
HŽ series 1161, rail.locomotive_class.weight, 129.0
Zagreb Railway Works, rail.locomotive_builder.locomotive_classes_built, HŽ series 1161

Answer: HŽ series 1161