Building Trainline’s AI Travel Assistant: How a 25-Year-Old Company Went Agentic

Trainline—the world’s leading rail and coach platform—helps millions of travelers get from point A to point B. Now, they’re using AI to make every step of the journey smoother. In this episode, Teresa Torres talks with David Eason (Principal Product Manager) Billie Bradley (Product Manager), and Matt Farrelly (Head of AI and Machine Learning) from Trainline about how they built Travel Assistant, an AI-powered travel companion that helps customers navigate disruptions, find real-time answers, and travel with confidence. They share how they: - Identified underserved traveler needs beyond ticketing - Built a fully agentic system from day one, combining orchestration, tools, and reasoning loops - Designed layered guardrails for safety, grounding, and human handoff - Expanded from 450 to 700,000 curated pages of information for retrieval - Developed LLM-as-judge evals and a custom user context simulator to measure quality in real-time - Balanced latency, UX, and reliability to make AI assistance feel trustworthy on the go It’s a behind-the-scenes look at how an established company is embracing new AI architectures to serve customers at scale.