Junior Machine Learning Engineer

About us

At Trainline, our purpose is to empower greener travel choices, connecting people and places. Trainline enables millions of travellers to find and book the best value tickets across carriers, fares, and journey options through our highly rated mobile app, website, and B2B partner channels.

Great journeys start with Trainline

We’re Europe’s leading independent rail platform, helping millions of travellers find and book the best-value rail and coach journeys across our app, website and partner channels.

Our job is to make the green travel choice the best choice. By building a better train travel experience, we help more people choose rail - creating a positive impact for customers, our business and the planet.

We’re a team of more than 1,000 Trainliners from over 50 nationalities, working across London, Paris, Barcelona, Milan, Edinburgh and Madrid. Now is a brilliant time to join us and help shape the future of travel.

Machine learning and AI are at the core of how Trainline is transforming travel, helping millions of customers make smarter, more sustainable journeys every day. Our ML models and AI solutions power critical aspects of our platform, including advanced search and recommendations across our mobile and web applications, pricing and routing optimisation, personalised experiences enhanced by agentic AI, data-driven marketing systems, and AI agents that improve customer support.

Our machine learning teams own the complete delivery lifecycle from ideation to production, working closely with stakeholders across the business to expand the understanding and impact of machine learning and AI throughout Trainline.

We are looking for a Junior Machine Learning Engineer to join a high-performing, deeply technical community of Machine Learning Engineers, Data Scientists and Data Engineers who tackle complex problems by combining Trainline's rich datasets with cutting-edge algorithms. You will be supported to grow your skills through hands‑on project work, close collaboration with more experienced colleagues, and a genuine culture of learning and development, while contributing to large-scale production systems that make a real difference to millions of customers.

• Work within cross-functional teams alongside data scientists, software engineers, data engineers and product managers
• Support the design and delivery of machine learning models and AI solutions that contribute to measurable impact for Trainline
• Get involved across the machine learning delivery lifecycle, including data exploration, feature engineering, model selection and evaluation
• Collaborate with stakeholders to help shape data products that make good use of Trainline's extensive datasets
• Contribute to the tools, frameworks and libraries that help accelerate our ML and AI delivery and improve our workflows
• Take part in our AI and ML community, sharing learning and building your experimentation skills alongside others

We'd love to hear from you if you have

• A good working knowledge of Python, including open-source data libraries such as Pandas, Num Py or Scikit-learn
• A background in Computer Science, Mathematics, Statistics or a similar quantitative discipline, whether through study or practical experience
• Some exposure to building or supporting machine learning models or AI solutions, gained through study, projects or early career experience
• An interest in areas such as predictive modelling, classification, regression, optimisation, NLP or recommendation systems
• A curious, collaborative approach and strong communication skills, with an eagerness to learn from others
• It would be helpful if you have had some exposure to Spark…